Selective tissue removal tool for use in medical applications and methods for making and using

ABSTRACT

The present disclosure relates generally to the field of tissue removal and more particularly to methods and devices for use in medical applications involving selective tissue removal. One exemplary method includes the steps of providing a tissue cutting instrument capable of distinguishing between target tissue to be removed and non-target tissue, urging the instrument against the target tissue and the non-target tissue, and allowing the instrument to cut the target tissue while automatically avoiding cutting of non-target tissue. Various tools for carrying out this method are also described.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. application Ser. No.13/007,578 filed Jan. 14, 2011 which is a Continuation in Part of U.S.application Ser. No. 12/490,295 filed Jun. 23, 2009 which claimspriority to: U.S. Provisional Application No. 61/075,006 filed Jun. 23,2008; U.S. Provisional Application No. 61/164,864 filed Mar. 30, 2009;and U.S. Provisional Application No. 61/164,883 filed Mar. 30, 2009.This application is a Continuation of U.S. application Ser. No.13/007,578 filed Jan. 14, 2011 which is also a Continuation in Part ofU.S. application Ser. No. 12/490,301 filed Jun. 23, 2009 which claimspriority to: U.S. Provisional Application No. 61/075,006 filed Jun. 23,2008; U.S. Provisional Application No. 61/164,864 filed Mar. 30, 2009;and U.S. Provisional Application No. 61/164,883 filed Mar. 30, 2009. Inaddition, this application is a Continuation of U.S. application Ser.No. 13/007,578 filed Jan. 14, 2011 which claims priority to U.S.Provisional Application No. 61/408,558 filed Oct. 29, 2010. Each ofthese applications is incorporated herein by reference as if set forthin full herein.

GOVERNMENT RIGHTS

This invention was made with government support under Grant No. R01HL087797 awarded by the National Institutes of Health. The governmenthas certain rights in the invention.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

FIELD OF THE INVENTION

Embodiments of the present invention relate to micro-scale andmillimeter-scale shredding devices that may, for example, be used toremove unwanted tissue or other material from selected locations withina body of a patient during a minimally invasive or other medicalprocedures and in particular embodiments multi-layer, multi-materialelectrochemical fabrication methods are used to, in whole or in part,form such devices.

BACKGROUND OF THE INVENTION

An electrochemical fabrication technique for forming three-dimensionalstructures from a plurality of adhered layers is being commerciallypursued by Microfabrica® Inc. (formerly MEMGen Corporation) of Van Nuys,Calif. under the name EFAB®.

Various electrochemical fabrication techniques were described in U.S.Pat. No. 6,027,630, issued on Feb. 22, 2000 to Adam Cohen. Someembodiments of this electrochemical fabrication technique allow theselective deposition of a material using a mask that includes apatterned conformable material on a support structure that isindependent of the substrate onto which plating will occur. Whendesiring to perform an electrodeposition using the mask, the conformableportion of the mask is brought into contact with a substrate, but notadhered or bonded to the substrate, while in the presence of a platingsolution such that the contact of the conformable portion of the mask tothe substrate inhibits deposition at selected locations. Forconvenience, these masks might be generically called conformable contactmasks; the masking technique may be generically called a conformablecontact mask plating process. More specifically, in the terminology ofMicrofabrica Inc. such masks have come to be known as INSTANT MASKS™ andthe process known as INSTANT MASKING™ or INSTANT MASK™ plating.Selective depositions using conformable contact mask plating may be usedto form single selective deposits of material or may be used in aprocess to form multi-layer structures. The teachings of the '630 patentare hereby incorporated herein by reference as if set forth in fullherein. Since the filing of the patent application that led to the abovenoted patent, various papers about conformable contact mask plating(i.e., INSTANT MASKING) and electrochemical fabrication have beenpublished:

-   -   (1) A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P.        Will, “EFAB Batch production of functional, fully-dense metal        parts with micro-scale features”, Proc. 9th Solid Freeform        Fabrication, The University of Texas at Austin, p 161, August        1998.    -   (2) A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P.        Will, “EFAB: Rapid, Low-Cost Desktop Micromachining of High        Aspect Ratio True 3-D MEMS”, Proc. 12th IEEE Micro Electro        Mechanical Systems Workshop, IEEE, p 244, January 1999.    -   (3) A. Cohen, “3-D Micromachining by Electrochemical        Fabrication”, Micromachine Devices, March 1999.    -   (4) G. Zhang, A. Cohen, U. Frodis, F. Tseng, F. Mansfeld, and P.        Will, “EFAB: Rapid Desktop Manufacturing of True 3-D        Microstructures”, Proc. 2nd International Conference on        Integrated MicroNanotechnology for Space Applications, The        Aerospace Co., April 1999.    -   (5) F. Tseng, U. Frodis, G. Zhang, A. Cohen, F. Mansfeld, and P.        Will, “EFAB: High Aspect Ratio, Arbitrary 3-D Metal        Microstructures using a Low-Cost Automated Batch Process”, 3rd        International Workshop on High Aspect Ratio MicroStructure        Technology (HARMST'99), June 1999.    -   (6) A. Cohen, U. Frodis, F. Tseng, G. Zhang, F. Mansfeld, and P.        Will, “EFAB: Low-Cost, Automated Electrochemical Batch        Fabrication of Arbitrary 3-D Microstructures”, Micromachining        and Microfabrication Process Technology, SPIE 1999 Symposium on        Micromachining and Microfabrication, September 1999.    -   (7) F. Tseng, G. Zhang, U. Frodis, A. Cohen, F. Mansfeld, and P.        Will, “EFAB: High Aspect Ratio, Arbitrary 3-D Metal        Microstructures using a Low-Cost Automated Batch Process”, MEMS        Symposium, ASME 1999 International Mechanical Engineering        Congress and Exposition, November, 1999.    -   (8) A. Cohen, “Electrochemical Fabrication (EFAB™)”, Chapter 19        of The MEMS Handbook, edited by Mohamed Gad-El-Hak, CRC Press,        2002.    -   (9) Microfabrication—Rapid Prototyping's Killer Application”,        pages 1-5 of the Rapid Prototyping Report, CAD/CAM Publishing,        Inc., June 1999.

An electrochemical deposition for forming multilayer structures may becarried out in a number of different ways as set forth in the abovepatent and publications. In one form, this process involves theexecution of three separate operations during the formation of eachlayer of the structure that is to be formed:

-   -   1. Selectively depositing at least one material by        electrodeposition upon one or more desired regions of a        substrate. Typically this material is either a structural        material or a sacrificial material.    -   2. Then, blanket depositing at least one additional material by        electrodeposition so that the additional deposit covers both the        regions that were previously selectively deposited onto, and the        regions of the substrate that did not receive any previously        applied selective depositions. Typically this material is the        other of a structural material or a sacrificial material.    -   3. Finally, planarizing the materials deposited during the first        and second operations to produce a smoothed surface of a first        layer of desired thickness having at least one region containing        the at least one material and at least one region containing at        least the one additional material.

After formation of the first layer, one or more additional layers may beformed adjacent to an immediately preceding layer and adhered to thesmoothed surface of that preceding layer. These additional layers areformed by repeating the first through third operations one or more timeswherein the formation of each subsequent layer treats the previouslyformed layers and the initial substrate as a new and thickeningsubstrate.

Once the formation of all layers has been completed, at least a portionof at least one of the materials deposited is generally removed by anetching process to expose or release the three-dimensional structurethat was intended to be formed. The removed material is a sacrificialmaterial while the material that forms part of the desired structure isa structural material.

The preferred method of performing the selective electrodepositioninvolved in the first operation is by conformable contact mask plating.In this type of plating, one or more conformable contact (CC) masks arefirst formed. The CC masks include a support structure onto which apatterned conformable dielectric material is adhered or formed. Theconformable material for each mask is shaped in accordance with aparticular cross-section of material to be plated (the pattern ofconformable material is complementary to the pattern of material to bedeposited). At least one CC mask is used for each unique cross-sectionalpattern that is to be plated.

The support for a CC mask is typically a plate-like structure formed ofa metal that is to be selectively electroplated and from which materialto be plated will be dissolved. In this typical approach, the supportwill act as an anode in an electroplating process. In an alternativeapproach, the support may instead be a porous or otherwise perforatedmaterial through which deposition material will pass during anelectroplating operation on its way from a distal anode to a depositionsurface. In either approach, it is possible for multiple CC masks toshare a common support, i.e. the patterns of conformable dielectricmaterial for plating multiple layers of material may be located indifferent areas of a single support structure. When a single supportstructure contains multiple plating patterns, the entire structure isreferred to as the CC mask while the individual plating masks may bereferred to as “submasks”. In the present application such a distinctionwill be made only when relevant to a specific point being made.

In preparation for performing the selective deposition of the firstoperation, the conformable portion of the CC mask is placed inregistration with and pressed against a selected portion of (1) thesubstrate, (2) a previously formed layer, or (3) a previously depositedportion of a layer on which deposition is to occur. The pressingtogether of the CC mask and relevant substrate occur in such a way thatall openings, in the conformable portions of the CC mask contain platingsolution. The conformable material of the CC mask that contacts thesubstrate acts as a barrier to electrodeposition while the openings inthe CC mask that are filled with electroplating solution act as pathwaysfor transferring material from an anode (e.g. the CC mask support) tothe non-contacted portions of the substrate (which act as a cathodeduring the plating operation) when an appropriate potential and/orcurrent are supplied.

An example of a CC mask and CC mask plating are shown in FIGS. 1A-1C.FIG. 1A shows a side view of a CC mask 8 consisting of a conformable ordeformable (e.g. elastomeric) insulator 10 patterned on an anode 12. Theanode has two functions. One is as a supporting material for thepatterned insulator 10 to maintain its integrity and alignment since thepattern may be topologically complex (e.g., involving isolated “islands”of insulator material). The other function is as an anode for theelectroplating operation. FIG. 1A also depicts a substrate 6, separatedfrom mask 8, onto which material will be deposited during the process offorming a layer. CC mask plating selectively deposits material 22 ontosubstrate 6 by simply pressing the insulator against the substrate thenelectrodepositing material through apertures 26 a and 26 b in theinsulator as shown in FIG. 1B. After deposition, the CC mask isseparated, preferably non-destructively, from the substrate 6 as shownin FIG. 1C.

The CC mask plating process is distinct from a “through-mask” platingprocess in that in a through-mask plating process the separation of themasking material from the substrate would occur destructively.Furthermore in a through mask plating process, opening in the maskingmaterial are typically formed while the masking material is in contactwith and adhered to the substrate. As with through-mask plating, CC maskplating deposits material selectively and simultaneously over the entirelayer. The plated region may consist of one or more isolated platingregions where these isolated plating regions may belong to a singlestructure that is being formed or may belong to multiple structures thatare being formed simultaneously. In CC mask plating as individual masksare not intentionally destroyed in the removal process, they may beusable in multiple plating operations.

Another example of a CC mask and CC mask plating is shown in FIGS.1D-1G. FIG. 1D shows an anode 12′ separated from a mask 8′ that includesa patterned conformable material 10′ and a support structure 20. FIG. 1Dalso depicts substrate 6 separated from the mask 8′. FIG. 1E illustratesthe mask 8′ being brought into contact with the substrate 6. FIG. 1Fillustrates the deposit 22′ that results from conducting a current fromthe anode 12′ to the substrate 6. FIG. 1G illustrates the deposit 22′ onsubstrate 6 after separation from mask 8′. In this example, anappropriate electrolyte is located between the substrate 6 and the anode12′ and a current of ions coming from one or both of the solution andthe anode are conducted through the opening in the mask to the substratewhere material is deposited. This type of mask may be referred to as ananodeless INSTANT MASK™ (AIM) or as an anodeless conformable contact(ACC) mask.

Unlike through-mask plating, CC mask plating allows CC masks to beformed completely separate from the substrate on which plating is tooccur (e.g. separate from a three-dimensional (3D) structure that isbeing formed). CC masks may be formed in a variety of ways, for example,using a photolithographic process. All masks can be generatedsimultaneously, e.g. prior to structure fabrication rather than duringit. This separation makes possible a simple, low-cost, automated,self-contained, and internally-clean “desktop factory” that can beinstalled almost anywhere to fabricate 3D structures, leaving anyrequired clean room processes, such as photolithography to be performedby service bureaus or the like.

An example of the electrochemical fabrication process discussed above isillustrated in FIGS. 2A-2F. These figures show that the process involvesdeposition of a first material 2 which is a sacrificial material and asecond material 4 which is a structural material. The CC mask 8, in thisexample, includes a patterned conformable material (e.g. an elastomericdielectric material) 10 and a support 12 which is made from depositionmaterial 2. The conformal portion of the CC mask is pressed againstsubstrate 6 with a plating solution 14 located within the openings 16 inthe conformable material 10. An electric current, from power supply 18,is then passed through the plating solution 14 via (a) support 12 whichdoubles as an anode and (b) substrate 6 which doubles as a cathode. FIG.2A illustrates that the passing of current causes material 2 within theplating solution and material 2 from the anode 12 to be selectivelytransferred to and plated on the substrate 6. After electroplating thefirst deposition material 2 onto the substrate 6 using CC mask 8, the CCmask 8 is removed as shown in FIG. 2B. FIG. 2C depicts the seconddeposition material 4 as having been blanket-deposited (i.e.non-selectively deposited) over the previously deposited firstdeposition material 2 as well as over the other portions of thesubstrate 6. The blanket deposition occurs by electroplating from ananode (not shown), composed of the second material, through anappropriate plating solution (not shown), and to the cathode; substrate6. The entire two-material layer is then planarized to achieve precisethickness and flatness as shown in FIG. 2D. After repetition of thisprocess for all layers, the multi-layer structure 20 formed of thesecond material 4 (i.e. structural material) is embedded in firstmaterial 2 (i.e. sacrificial material) as shown in FIG. 2E. The embeddedstructure is etched to yield the desired device, i.e. structure 20, asshown in FIG. 2F.

Various components of an exemplary manual electrochemical fabricationsystem 32 are shown in FIGS. 3A-3C. The system 32 consists of severalsubsystems 34, 36, 38, and 40. The substrate holding subsystem 34 isdepicted in the upper portions of each of FIGS. 3A-3C and includesseveral components: (1) a carrier 48, (2) a metal substrate 6 onto whichthe layers are deposited, and (3) a linear slide 42 capable of movingthe substrate 6 up and down relative to the carrier 48 in response todrive force from actuator 44. Subsystem 34 also includes an indicator 46for measuring differences in vertical position of the substrate whichmay be used in setting or determining layer thicknesses and/ordeposition thicknesses. The subsystem 34 further includes feet 68 forcarrier 48 which can be precisely mounted on subsystem 36.

The CC mask subsystem 36 shown in the lower portion of FIG. 3A includesseveral components: (1) a CC mask 8 that is actually made up of a numberof CC masks (i.e. submasks) that share a common support/anode 12, (2)precision X-stage 54, (3) precision Y-stage 56, (4) frame 72 on whichthe feet 68 of subsystem 34 can mount, and (5) a tank 58 for containingthe electrolyte 16. Subsystems 34 and 36 also include appropriateelectrical connections (not shown) for connecting to an appropriatepower source (not shown) for driving the CC masking process.

The blanket deposition subsystem 38 is shown in the lower portion ofFIG. 3B and includes several components: (1) an anode 62, (2) anelectrolyte tank 64 for holding plating solution 66, and (3) frame 74 onwhich feet 68 of subsystem 34 may sit. Subsystem 38 also includesappropriate electrical connections (not shown) for connecting the anodeto an appropriate power supply (not shown) for driving the blanketdeposition process.

The planarization subsystem 40 is shown in the lower portion of FIG. 3Cand includes a lapping plate 52 and associated motion and controlsystems (not shown) for planarizing the depositions.

In addition to teaching the use of CC masks for electrodepositionpurposes, the '630 patent also teaches that the CC masks may be placedagainst a substrate with the polarity of the voltage reversed andmaterial may thereby be selectively removed from the substrate. Itindicates that such removal processes can be used to selectively etch,engrave, and polish a substrate, e.g., a plaque.

The '630 patent further indicates that the electroplating methods andarticles disclosed therein allow fabrication of devices from thin layersof materials such as, e.g., metals, polymers, ceramics, andsemiconductor materials. It further indicates that although theelectroplating embodiments described therein have been described withrespect to the use of two metals, a variety of materials, e.g.,polymers, ceramics and semiconductor materials, and any number of metalscan be deposited either by the electroplating methods therein, or inseparate processes that occur throughout the electroplating method. Itindicates that a thin plating base can be deposited, e.g., bysputtering, over a deposit that is insufficiently conductive (e.g., aninsulating layer) so as to enable subsequent electroplating. It alsoindicates that multiple support materials (i.e. sacrificial materials)can be included in the electroplated element allowing selective removalof the support materials.

The '630 patent additionally teaches that the electroplating methodsdisclosed therein can be used to manufacture elements having complexmicrostructure and close tolerances between parts. An example is givenwith the aid of FIGS. 14A-14E of that patent. In the example, elementshaving parts that fit with close tolerances, e.g., having gaps betweenabout 1-5 um, including electroplating the parts of the device in anunassembled, preferably pre-aligned, state and once fabricated. In suchembodiments, the individual parts can be moved into operational relationwith each other or they can simply fall together. Once together theseparate parts may be retained by clips or the like.

Another method for forming microstructures from electroplated metals(i.e. using electrochemical fabrication techniques) is taught in U.S.Pat. No. 5,190,637 to Henry Guckel, entitled “Formation ofMicrostructures by Multiple Level Deep X-ray Lithography withSacrificial Metal layers”. This patent teaches the formation of metalstructure utilizing through mask exposures. A first layer of a primarymetal is electroplated onto an exposed plating base to fill a void in aphotoresist (the photoresist forming a through mask having a desiredpattern of openings), the photoresist is then removed and a secondarymetal is electroplated over the first layer and over the plating base.The exposed surface of the secondary metal is then machined down to aheight which exposes the first metal to produce a flat uniform surfaceextending across both the primary and secondary metals. Formation of asecond layer may then begin by applying a photoresist over the firstlayer and patterning it (i.e. to form a second through mask) and thenrepeating the process that was used to produce the first layer toproduce a second layer of desired configuration. The process is repeateduntil the entire structure is formed and the secondary metal is removedby etching. The photoresist is formed over the plating base or previouslayer by casting and patterning of the photoresist (i.e. voids formed inthe photoresist) are formed by exposure of the photoresist through apatterned mask via X-rays or UV radiation and development of the exposedor unexposed areas.

The '637 patent teaches the locating of a plating base onto a substratein preparation for electroplating materials onto the substrate. Theplating base is indicated as typically involving the use of a sputteredfilm of an adhesive metal, such as chromium or titanium, and then asputtered film of the metal that is to be plated. It is also taught thatthe plating base may be applied over an initial layer of sacrificialmaterial (i,e. a layer or coating of a single material) on the substrateso that the structure and substrate may be detached if desired. In suchcases after formation of the structure the sacrificial material formingpart of each layer of the structure may be removed along the initialsacrificial layer to free the structure. Substrate materials mentionedin the '637 patent include silicon, glass, metals, and silicon withprotected semiconductor devices. A specific example of a plating baseincludes about 150 angstroms of titanium and about 300 angstroms ofnickel, both of which are sputtered at a temperature of 160° C. Inanother example it is indicated that the plating base may consist of 150angstroms of titanium and 150 angstroms of nickel where both are appliedby sputtering.

Electrochemical Fabrication provides the ability to form prototypes andcommercial quantities of miniature objects, parts, structures, devices,and the like at reasonable costs and in reasonable times. In fact,Electrochemical Fabrication is an enabler for the formation of manystructures that were hitherto impossible to produce. ElectrochemicalFabrication opens the spectrum for new designs and products in manyindustrial fields. Even though Electrochemical Fabrication offers thisnew capability and it is understood that Electrochemical Fabricationtechniques can be combined with designs and structures known withinvarious fields to produce new structures, certain uses forElectrochemical Fabrication provide designs, structures, capabilitiesand/or features not known or obvious in view of the state of the art.

A need exists in various fields for miniature devices having improvedcharacteristics, reduced fabrication times, reduced fabrication costs,simplified fabrication processes, greater versatility in device design,improved selection of materials, improved material properties, more costeffective and less risky production of such devices, and/or moreindependence between geometric configuration and the selectedfabrication process.

The medical device field is one area which can benefit from the abilityto produce a device (e.g., implantable devices, tools used in medicalprocedures, including surgical procedures and minimally invasiveprocedures, etc.), or certain parts of the device, with very smalldimensions, or from the ability to produce devices or parts of thedevice with small dimensions, but with improved performance overexisting products and procedures. Some medical procedures include, orconsist primarily of the removal of tissue from a subject. The tissuecan be native to the subject or tissue which may be considered to beforeign tissue (e.g. tumor mass).

Some devices with relatively large dimensions risk removing unintendedtissue from the subject, or damaging the unintended tissue. There is aneed for tissue removal devices which have small dimensions and improvedfunctionality which allow them to more safely remove only the desiredtissue from the patient. There is also a need for tissue removal deviceswhich have small dimensions and improved functionality over existingproducts and procedures which allow them to more efficiently removetissue from the patient.

One portion of the body in which tissue can be removed to treat avariety of conditions is the spine area. Tissue removal devices for thespine are needed that can produced with sufficiently small dimensionand/or that have increased performance over existing techniques. Forexample, a herniated disc or bulging disc can be treated by performing adiscectomy, e.g. by removing all or part of the nucleus pulposus of thedamaged disc. Such procedures may also involve a laminotomy orlaminectomy wherein a portion or all of a lamina may be removed to allowaccess to the herniated disc. Artificial disc replacement (total orpartial) is another example of a procedure which requires the removal ofall or a portion of the disc, which is replaced with an artificialdevice or material.

Prior art tissue removal devices often remove tissue in large pieces,having dimensions well over 2 mm. The tissue pieces are removed throughan aspiration lumen typically 3.5 to 5 mm in diameter. Since the tissuepieces being removed commonly have dimensions that are 1 to 2 lumendiameters in length, the tissue pieces can often clog the tissue removallumen.

Tissue removal devices are needed which can be produced with sufficientmechanical complexity and a small size so that they can both safely andmore efficiently remove tissue from a subject, and/or remove tissue in aless invasive procedure and/or with less damage to adjacent tissue suchthat risks are lowered and recovery time is improved. Additionally,tissue removal devices are needed which can aid a surgeon byautomatically selecting between target tissue to be removed andnon-target tissue that is to be left intact.

SUMMARY OF THE DISCLOSURE

According to some aspects of the disclosure, methods of selectivelyremoving tissue are provided. One exemplary method includes the steps ofproviding a tissue cutting instrument capable of distinguishing betweentarget tissue to be removed and non-target tissue, urging the instrumentagainst the target tissue and the non-target tissue, and allowing theinstrument to cut the target tissue while automatically avoiding cuttingof non-target tissue.

According to some aspects of the disclosure, debridement instruments areprovided. One exemplary instrument includes an elongated introducerhaving a proximal end and a distal end, and a cutter housing locatednear the distal end of the introducer. In this embodiment, at least onecutter element is rotably mounted to the cutter housing. The cutterelement is configured to remove portions of soft tissue from a body. Theinstrument also includes a tissue removal lumen extending along theintroducer and having an inlet within the cutter housing. The lumen isconfigured to remove the tissue portions cut by the cutter element. Theinstrument is configured to ensure that the portions of removed tissuehave a maximum dimension less than about 2 mm across before they passthrough the tissue removal lumen inlet. In some embodiments havinglarger instruments, the maximum tissue dimension is larger than about 2mm.

According to some aspects of the disclosure, a method of selectivelyremoving soft target tissue from a body includes providing an instrumentcomprising an elongated introducer, a cutter housing located near adistal end of the introducer, and at least one cutter element rotablymounted to the cutter housing. The cutter element is rotated, and thecutter element and soft target tissue are caused to come into contactwith one another such that the rotating cutter element cuts off portionsof the soft target tissue. The instrument is configured to cut thetissue in portions having a maximum dimension less than 2 mm across. Thecut tissue portions are removed through a tissue removal lumen extendingfrom adjacent the cutter element and along the introducer.

Other aspects of the disclosure will be apparent to those of skill inthe art upon review of the teachings herein. The various embodiments ofthe disclosure, set forth explicitly herein or otherwise ascertainedfrom the teachings herein, may address one or more of the above needsthat are not met by the prior art, alone or in combination, oralternatively may address some other need ascertained from the teachingsherein. It is not necessarily intended that all needs be addressed byany single aspect of the disclosure even though that may be the casewith regard to some aspects.

The disclosure of the present invention provides to number of deviceembodiments which may be fabricated, but are not necessarily fabricated,from a plurality of formed and adhered layers with each successive layerincluding at least two materials, one of which is a structural materialand the other of which is a sacrificial material, and wherein eachsuccessive layer defines a successive cross-section of thethree-dimensional structure, and wherein the forming of each of theplurality of successive layers includes: (i) depositing a first of theat least two materials; (ii) depositing a second of the at least twomaterials; and (B) after the forming of the plurality of successivelayers, separating at least a portion of the sacrificial material fromthe structural material to reveal the three-dimensional structure. Insome embodiments, the device may include a plurality of componentsmovable relative to one another which contain etching holes which may bealigned during fabrication and during release from at least a portion ofthe sacrificial material.

Other aspects of the disclosure will be understood by those of skill inthe art upon review of the teachings herein. Other aspects of thedisclosure may involve combinations of the above noted aspects of thedisclosure. These other aspects of the disclosure may provide variouscombinations of the aspects presented above as well as provide otherconfigurations, structures, functional relationships, and processes thathave not been specifically set forth above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C schematically depict side views of various stages of a CCmask plating process, while FIGS. 1D-G schematically depict a side viewsof various stages of a CC mask plating process using a different type ofCC mask.

FIGS. 2A-2F schematically depict side views of various stages of anelectrochemical fabrication process as applied to the formation of aparticular structure where a sacrificial material is selectivelydeposited while a structural material is blanket deposited.

FIGS. 3A-3C schematically depict side views of various examplesubassemblies that may be used in manually implementing theelectrochemical fabrication method depicted in FIGS. 2A-2F.

FIGS. 4A-4F schematically depict the formation of a first layer of astructure using adhered mask plating where the blanket deposition of asecond material overlays both the openings between deposition locationsof a first material and the first material itself

FIG. 4G depicts the completion of formation of the first layer resultingfrom planarizing the deposited materials to a desired level.

FIGS. 4H and 4I respectively depict the state of the process afterformation of the multiple layers of the structure and after release ofthe structure from the sacrificial material.

FIGS. 5-7 illustrate an exemplary embodiment of a working end of atissue removal device which can be fabricated wholly or in part byelectrochemical fabrication techniques, such as those described orreferenced herein.

FIG. 8 illustrates a perspective view of an exemplary gear train systemwhich can be included in any suitable working end described herein todrive the rotation of the blades.

FIG. 9 shows a portion of two adjacent gears formed from a multi-layer,multi-material electrochemical fabrication process.

FIG. 10 illustrates an exemplary embodiment of a first gearconfiguration for assembled fabrication which allows for minimizingbacklash while still meeting minimum feature size limitations in bothgear tooth spacing as well as axle shaft and guide hole, bearing orbushing spacing.

FIGS. 11 and 12 show three gears in an “as fabricated” configuration.

FIGS. 13 and 14 highlight the proximal end and distal end, respectively,of the gear trains shown in FIG. 8, which incorporate a multi-tieredgear design.

FIG. 15 illustrates an alternative embodiment of a gear formation thatcan be used in any of the tissue removal devices herein.

FIGS. 16-19 illustrate yet another alternative gear train design whichmay allow meeting minimum feature size requirements while providing morerobust gears along with back lash not being excessively large.

FIG. 20 illustrates a partial view of the working end of tissue removaldevice in which the top portion and one side wall of housing have beenremoved to show one of the exemplary gear trains from FIG. 8 disposed inhousing.

FIG. 21 provides a perspective cross-sectional view of the rear portionof a working end of a device according to an embodiment of thedisclosure with the back shielding and a portion of the gears cut awayso that the relationship between the gears, the upper and lower gearenclosures, and outer housing of the device can be seen.

FIG. 22 illustrates an alternative drive mechanism coupler having aD-shaped hole or bore.

FIGS. 23A-27C illustrate alternative exemplary embodiments of drivemechanisms which can power the drive trains in the working end, any ofwhich may be adapted to be included in any suitable tissue removaldevice, such as those described herein.

FIG. 28 illustrates an exemplary coupling between an introducer and aworking end, wherein the introducer is adapted to introduce, orposition, the working end at the target tissue site.

FIG. 29 illustrates an exemplary articulatable introducer includingnon-articulating portion and articulating portion, wherein theintroducer is coupled to working end.

FIG. 30 shows an introducer and a working end, including shredders,coupled together, with a portion of introducer disposed within adelivery member.

FIG. 31A illustrates a portion of a housing of a working end, includingfixed tissue removal elements, an optional irrigation port, and aslidable element disposed within a bore in a housing.

FIG. 31B shows an exemplary embodiment of a working end that is adaptedto be actuated to rotate a working end relative to an introducer.

FIGS. 32A-32C illustrate a device and methods for providing a space forvisualization of the target site, and/or target tissue.

FIGS. 33A-33C illustrate an alternative arrangement of the deliverysystem for visualizing the working area.

FIG. 34A-34F illustrate an exemplary procedure for treating a herniateddisc by removing nucleus tissue using a tissue removal device asdescribed herein.

FIG. 35 illustrates an exemplary embodiment wherein the axes of rotationof the rotors for a set of blades are substantially orthogonal to thelongitudinal axis of at least the working end.

FIG. 36 shows a distal end of a working end including a single rotor andstator wherein the stator includes fingers or other elements that workwith the rotor to cause shredding or other disruption of the tissue intosmall pieces that may be removed via the device from the body of apatient.

FIG. 37 shows exemplary blade profiles for removing soft tissue.

FIG. 38 shows some additional exemplary blade types, supplementing someof the blade types shown in FIG. 37.

FIGS. 39A-39C illustrate exemplary embodiments of double rotor bladedesigns.

FIGS. 40A (perspective view) and 40B (top view) illustrate analternative embodiment of a working end in which tissue is captured andprocessed in multiple steps.

FIG. 41 illustrates an alternative design in which a plurality of bladerotors directs tissue (not shown) towards a set of vertical cutterswhich are fixed in place.

FIG. 42 shows an alternative embodiment of a ‘hybrid’ blade with teeththat are capable of both piercing and cutting into tissue to entrain it.

FIG. 43 illustrates an optional blade stagger design in which the tipsof teeth are staggered from one another as measured circumferentially orin an offset angular increment relative to adjacent blade tips.

FIG. 44 illustrates an exemplary embodiment of components of a devicethat are formed in one configuration but separated from a finalconfiguration and are moved relatively toward one another after releasefrom sacrificial material.

FIG. 45 shows an exemplary embodiment in which a gear or boss isfabricated in an “as-formed” configuration in which it is out of planewith material which the gear or boss will ultimately be in-plane with ina final configuration after formation.

FIG. 46 illustrates an alternative embodiment similar to FIG. 44,wherein a slide plate includes a protrusion on one side adapted to fitwithin a channel

FIGS. 47A-47C illustrate an exemplary embodiment of a working endincluding a gear train and two shredder rotors.

FIGS. 48A-48C illustrate an embodiment of a tissue removal deviceincluding a core cutting saw 740 with a plurality of tissue removaldevices 742 therein.

FIG. 49 provides a schematic illustration of a plurality (i.e. 5 asshown) stacked tissue shredding devices having individual and stackedconfigurations providing a large area tissue removal surface having adesired configuration (e.g. circular configuration).

FIGS. 50A and 50B provide a schematic illustration of a shredding ortissue removal device, i.e. working end, located within a lumen havingan expanded distal end and a smaller lumen which may be used to feedadditional tools or elements into or beyond the expanded distal end ofthe lumen.

FIGS. 51A and 51B provide closed (compacted) and open (expanded) viewsof a sample device according to a procedural embodiment of thedisclosure.

FIGS. 52A-52F illustrate the use of the devices of FIGS. 50A-50B and51A-51B in a thrombectomy application.

FIGS. 53A-53D show another exemplary embodiment of a tissue removaldevice.

FIGS. 54A-54C show an exemplary cutter head assembly 5332 that may beused with debriding device 5310, shown in FIGS. 53A-53D.

FIGS. 55A-55D show further details of the lug bearing of cutter headassembly 5332, shown in FIGS. 54A-54C.

FIGS. 56A-56H show further details of cutter head assembly 5332, shownin FIGS. 54A-54C.

FIGS. 57A-57J show details of an exemplary rotor housing assembly 5420′.

FIGS. 58-65 depict various other aspects of cutting blades useful forselective tissue removal, according to aspects of the present invention.

FIGS. 66A-66M show views of 13 more examples of cutter heads constructedaccording to aspects of the present invention.

DETAILED DESCRIPTION

Electrochemical Fabrication in General

FIGS. 1A-1G, 2A-2F, and 3A-3C illustrate various features of one form ofelectrochemical fabrication. Other electrochemical fabricationtechniques are set forth in the '630 patent referenced above, in thevarious previously incorporated publications, in various other patentsand patent applications incorporated herein by reference. Still othersmay be derived from combinations of various approaches described inthese publications, patents, and applications, or are otherwise known orascertainable by those of skill in the art from the teachings set forthherein. All of these techniques may be combined with those of thevarious embodiments of various aspects of the disclosure to yieldenhanced embodiments. Still other embodiments may be derived fromcombinations of the various embodiments explicitly set forth herein.

FIGS. 4A-4I illustrate various stages in the formation of a single layerof a multi-layer fabrication process where a second metal is depositedon a first metal as well as in openings in the first metal so that thefirst and second metal form part of the layer. In FIG. 4A a side view ofa substrate 82 is shown, onto which patternable photoresist 84 is castas shown in FIG. 4B. In FIG. 4C, a pattern of resist is shown thatresults from the curing, exposing, and developing of the resist. Thepatterning of the photoresist 84 results in openings or apertures92(a)-92(c) extending from a surface 86 of the photoresist through thethickness of the photoresist to surface 88 of the substrate 82. In FIG.4D a metal 94 (e.g. nickel) is shown as having been electroplated intothe openings 92(a)-92(c). In FIG. 4E the photoresist has been removed(i.e. chemically stripped) from the substrate to expose regions of thesubstrate 82 which are not covered with the first metal 94. In FIG. 4F asecond metal 96 (e.g. silver) is shown as having been blanketelectroplated over the entire exposed portions of the substrate 82(which is conductive) and over the first metal 94 (which is alsoconductive). FIG. 4G depicts the completed first layer of the structurewhich has resulted from the planarization of the first and second metalsdown to a height that exposes the first metal and sets a thickness forthe first layer. In FIG. 4H the result of repeating the process stepsshown in FIGS. 4B-4G several times to form a multi-layer structure areshown where each layer consists of two materials. For most applications,one of these materials is removed as shown in FIG. 4I to yield a desired3-D structure 98 (e.g. component or device).

Various embodiments of various aspects of the disclosure are directed toformation of three-dimensional structures from materials some of whichmay be electrodeposited or electroless deposited. Some of thesestructures may be formed form a single build level formed from one ormore deposited materials while others are formed from a plurality ofbuild layers each including at least two materials (e.g. two or morelayers, more preferably five or more layers, and most preferably ten ormore layers). In some embodiments, layer thicknesses may be as small asone micron or as large as fifty microns. In other embodiments, thinnerlayers may be used while in other embodiments, thicker layers may beused. In some embodiments structures having features positioned withmicron level precision and minimum features size on the order of tens ofmicrons are to be formed. In other embodiments structures with lessprecise feature placement and/or larger minimum features may be formed.In still other embodiments, higher precision and smaller minimum featuresizes may be desirable. In the present application meso-scale andmillimeter scale have the same meaning and refer to devices that mayhave one or more dimensions extending into the 0.5-20 millimeter range,or somewhat larger and with features positioned with precision in the10-100 micron range and with minimum features sizes on the order of 100microns.

The various embodiments, alternatives, and techniques disclosed hereinmay form multi-layer structures using a single patterning technique onall layers or using different patterning techniques on different layers.For example, various embodiments of the disclosure may perform selectivepatterning operations using conformable contact masks and maskingoperations (i.e. operations that use masks which are contacted to butnot adhered to a substrate), proximity masks and masking operations(i,e. operations that use masks that at least partially selectivelyshield a substrate by their proximity to the substrate even if contactis not made), non-conformable masks and masking operations (i.e. masksand operations based on masks whose contact surfaces are notsignificantly conformable), and/or adhered masks and masking operations(masks and operations that use masks that are adhered to a substrateonto which selective deposition or etching is to occur as opposed toonly being contacted to it). Conformable contact masks, proximity masks,and non-conformable contact masks share the property that they arepreformed and brought to, or in proximity to, a surface which is to betreated (i.e. the exposed portions of the surface are to be treated).These masks can generally be removed without damaging the mask or thesurface that received treatment to which they were contacted, or locatedin proximity to. Adhered masks are generally formed on the surface to betreated (i.e. the portion of that surface that is to be masked) andbonded to that surface such that they cannot be separated from thatsurface without being completely destroyed damaged beyond any point ofreuse. Adhered masks may be formed in a number of ways including (1) byapplication of a photoresist, selective exposure of the photoresist, andthen development of the photoresist, (2) selective transfer ofpre-patterned masking material, and/or (3) direct formation of masksfrom computer controlled depositions of material.

Patterning operations may be used in selectively depositing materialand/or may be used in the selective etching of material. Selectivelyetched regions may be selectively filled in or filled in via blanketdeposition, or the like, with a different desired material. In someembodiments, the layer-by-layer build up may involve the simultaneousformation of portions of multiple layers. In some embodiments,depositions made in association with some layer levels may result indepositions to regions associated with other layer levels (i.e. regionsthat lie within the top and bottom boundary levels that define adifferent layer's geometric configuration). Such use of selectiveetching and interlaced material deposition in association with multiplelayers is described in U.S. patent application Ser. No. 10/434,519, bySmalley, now U.S. Pat. No. 7,252,861, and entitled “Methods of andApparatus for Electrochemically Fabricating Structures Via InterlacedLayers or Via Selective Etching and Filling of Voids layer elements”which is hereby incorporated herein by reference as if set forth infull.

Temporary substrates on which structures may be formed may be of thesacrificial-type (i.e., destroyed or damaged during separation ofdeposited materials to the extent they cannot be reused),non-sacrificial-type (i.e. not destroyed or excessively damaged, i.e.not damaged to the extent they may not be reused, e.g. with asacrificial or release layer located between the substrate and theinitial layers of a structure that is formed). Non-sacrificialsubstrates may be considered reusable, with little or no rework (e.g.replanarizing one or more selected surfaces or applying a release layer,and the like) though they may or may not be reused for a variety ofreasons.

Definitions

This section of the specification is intended to set forth definitionsfor a number of specific terms that may be useful in describing thesubject matter of the various embodiments of the disclosure describedherein. It is believed that the meanings of most if not all of theseterms is clear from their general use in the specification but they areset forth hereinafter to remove any ambiguity that may exist It isintended that these definitions be used in understanding the scope andlimits of any claims that use these specific terms. As far asinterpretation of the claims of this patent disclosure are concerned, itis intended that these definitions take precedence over anycontradictory definitions or allusions found in any materials which areincorporated herein by reference.

“Build” as used herein refers, as a verb, to the process of building adesired structure or plurality of structures from a plurality of appliedor deposited materials which are stacked and adhered upon application ordeposition or, as a noun, to the physical structure or structures formedfrom such a process. Depending on the context in which the term is used,such physical structures may include a desired structure embedded withina sacrificial material or may include only desired physical structureswhich may be separated from one another or may require dicing and/orslicing to cause separation.

“Build axis” or “build orientation” is the axis or orientation that issubstantially perpendicular to substantially planar levels of depositedor applied materials that are used in building up a structure. Theplanar levels of deposited or applied materials may be or may not becompletely planar but are substantially so in that the overall extent oftheir cross-sectional dimensions are significantly greater than theheight of any individual deposit or application of material (e.g. 100,500, 1000, 5000, or more times greater). The planar nature of thedeposited or applied materials may come about from use of a process thatleads to planar deposits or it may result from a planarization process(e.g. a process that includes mechanical abrasion, e.g. lapping, flycutting, grinding, or the like) that is used to remove material regionsof excess height. Unless explicitly noted otherwise, “vertical” as usedherein refers to the build axis or nominal build axis (if the layers arenot stacking with perfect registration) while “horizontal” refers to adirection within the plane of the layers (i.e. the plane that issubstantially perpendicular to the build axis).

“Build layer” or “layer of structure” as used herein does not refer to adeposit of a specific material but instead refers to a region of a buildlocated between a lower boundary level and an upper boundary level whichgenerally defines a single cross-section of a structure being formed orstructures which are being formed in parallel. Depending on the detailsof the actual process used to form the structure, build layers aregenerally formed on and adhered to previously formed build layers. Insome processes the boundaries between build layers are defined byplanarization operations which result in successive build layers beingformed on substantially planar upper surfaces of previously formed buildlayers. In some embodiments, the substantially planar upper surface ofthe preceding build layer may be textured to improve adhesion betweenthe layers. In other build processes, openings may exist in or be formedin the upper surface of a previous but only partially formed buildlayers such that the openings in the previous build layers are filledwith materials deposited in association with current build layers whichwill cause interlacing of build layers and material deposits. Suchinterlacing is described in U.S. patent application Ser. No. 10/434,519,now U.S. Pat. No. 7,252,861. This referenced application is incorporatedherein by reference as if set forth in full. In most embodiments, abuild layer includes at least one primary structural material and atleast one primary sacrificial material. However, in some embodiments,two or more primary structural materials may be used without a primarysacrificial material (e.g. when one primary structural material is adielectric and the other is a conductive material). In some embodiments,build layers are distinguishable from each other by the source of thedata that is used to yield patterns of the deposits, applications,and/or etchings of material that form the respective build layers. Forexample, data descriptive of a structure to be formed which is derivedfrom data extracted from different vertical levels of a datarepresentation of the structure define different build layers of thestructure. The vertical separation of successive pairs of suchdescriptive data may define the thickness of build layers associatedwith the data. As used herein, at times, “build layer” may be looselyreferred simply as “layer”. In many embodiments, deposition thickness ofprimary structural or sacrificial materials (i.e. the thickness of anyparticular material after it is deposited) is generally greater than thelayer thickness and a net deposit thickness is set via one or moreplanarization processes which may include, for example, mechanicalabrasion (e.g. lapping, fly cutting, polishing, and the like) and/orchemical etching (e.g. using selective or non-selective etchants). Thelower boundary and upper boundary for a build layer may be set anddefined in different ways. From a design point of view they may be setbased on a desired vertical resolution of the structure (which may varywith height). From a data manipulation point of view, the vertical layerboundaries may be defined as the vertical levels at which datadescriptive of the structure is processed or the layer thickness may bedefined as the height separating successive levels of cross-sectionaldata that dictate how the structure will be formed. From a fabricationpoint of view, depending on the exact fabrication process used, theupper and lower layer boundaries may be defined in a variety ofdifferent ways. For example by planarization levels or effectiveplanarization levels (e.g. lapping levels, fly cutting levels, chemicalmechanical polishing levels, mechanical polishing levels, verticalpositions of structural and/or sacrificial materials after relativelyuniform etch back following a mechanical or chemical mechanicalplanarization process). For example, by levels at which process steps oroperations are repeated. At levels at which, at least theoretically,lateral extends of structural material can be changed to define newcross-sectional features of a structure.

“Layer thickness” is the height along the build axis between a lowerboundary of a build layer and an upper boundary of that build layer.

“Planarization” is a process that tends to remove materials, above adesired plane, in a substantially non-selective manner such that alldeposited materials are brought to a substantially common height ordesired level (e.g. within 20%, 10%, 5%, or even 1% of a desired layerboundary level). For example, lapping removes material in asubstantially non-selective manner though some amount of recession onematerial or another may occur (e.g. copper may recess relative tonickel). Planarization may occur primarily via mechanical means, e.g.lapping, grinding, fly cutting, milling, sanding, abrasive polishing,frictionally induced melting, other machining operations, or the like(i.e. mechanical planarization). Mechanical planarization maybe followedor proceeded by thermally induced planarization (e.g. melting) orchemically induced planarization (e.g. etching). Planarization may occurprimarily via a chemical and/or electrical means (e.g. chemical etching,electrochemical etching, or the like). Planarization may occur via asimultaneous combination of mechanical and chemical etching (e.g.chemical mechanical polishing (CMP)).

“Structural material” as used herein refers to a material that remainspart of the structure when put into use.

“Supplemental structural material” as used herein refers to a materialthat forms part of the structure when the structure is put to use but isnot added as part of the build layers but instead is added to aplurality of layers simultaneously (e.g. via one or more coatingoperations that applies the material, selectively or in a blanketfashion, to a one or more surfaces of a desired build structure that hasbeen released from a sacrificial material.

“Primary structural material” as used herein is a structural materialthat forms part of a given build layer and which is typically depositedor applied during the formation of that build layer and which makes upmore than 20% of the structural material volume of the given buildlayer. In some embodiments, the primary structural material may be thesame on each of a plurality of build layers or it may be different ondifferent build layers. In some embodiments, a given primary structuralmaterial may be formed from two or more materials by the alloying ordiffusion of two or more materials to form a single material.

“Secondary structural material” as used herein is a structural materialthat forms part of a given build layer and is typically deposited orapplied during the formation of the given build layer but is not aprimary structural material as it individually accounts for only a smallvolume of the structural material associated with the given layer. Asecondary structural material will account for less than 20% of thevolume of the structural material associated with the given layer. Insome preferred embodiments, each secondary structural material mayaccount for less than 10%, 5%, or even 2% of the volume of thestructural material associated with the given layer. Examples ofsecondary structural materials may include seed layer materials,adhesion layer materials, harrier layer materials (e.g. diffusionbarrier material), and the like. These secondary structural materialsare typically applied to form coatings having thicknesses less than 2microns, 1 micron, 0.5 microns, or even 0.2 microns). The coatings mayhe applied in a conformal or directional manner (e.g. via CND, PVD,electroless deposition, or the like). Such coatings may be applied in ablanket manner or in a selective manner. Such coatings may be applied ina planar manner (e.g. over previously planarized layers of material) astaught in U.S. patent application Ser. No. 10/607,931. in otherembodiments, such coatings may be applied in a non-planar manner, forexample, in openings in and over a patterned masking material that hasbeen applied to previously planarized layers of material as taught inU.S. patent application Ser. No. 10/841,383. These referencedapplications are incorporated herein by reference as if set forth infull herein.

“Functional structural material” as used herein is a structural materialthat would have been removed as a sacrificial material but for itsactual or effective encapsulation by other structural materials.Effective encapsulation refers, for example, to the inability of anetchant to attack the functional structural material due toinaccessibility that results from a very small area of exposure and/ordue to an elongated or tortuous exposure path. For example, large(10,000 μm²) but thin (e.g. less than 0.5 microns) regions ofsacrificial copper sandwiched between deposits of nickel may defineregions of functional structural material depending on ability of arelease etchant to remove the sandwiched copper.

“Sacrificial material” is material that forms part of a build layer butis not a structural material. Sacrificial material on a given buildlayer is separated from structural material on that build layer afterformation of that build layer is completed and more generally is removedfrom a plurality of layers after completion of the formation of theplurality of layers during a “release” process that removes the bulk ofthe sacrificial material or materials. In general sacrificial materialis located on a build layer during the formation of one, two, or moresubsequent build layers and is thereafter removed in a manner that doesnot lead to a planarized surface. Materials that are applied primarilyfor masking purposes, i.e. to allow subsequent selective deposition oretching of a material, e.g. photoresist that is used in forming a buildlayer but does not form part of the build layer) or that exist as partof a build for less than one or two complete build layer formationcycles are not considered sacrificial materials as the term is usedherein but instead shall be referred as masking materials or astemporary materials. These separation processes are sometimes referredto as a release process and may or may not involve the separation ofstructural material from a build substrate. In many embodiments,sacrificial material within a given build layer is not removed until allbuild layers making up the three-dimensional structure have been formed.Of course sacrificial material may be, and typically is, removed fromabove the upper level of a current build layer during planarizationoperations during the formation of the current build layer. Sacrificialmaterial is typically removed via a chemical etching operation but insome embodiments may be removed via a melting operation orelectrochemical etching operation. In typical structures, the removal ofthe sacrificial material (i.e. release of the structural material fromthe sacrificial material) does not result in planarized surfaces butinstead results in surfaces that are dictated by the boundaries ofstructural materials located on each build layer. Sacrificial materialsare typically distinct from structural materials by having differentproperties there from (e.g. chemical etchability, hardness, meltingpoint, etc.) but in some cases, as noted previously, what would havebeen a sacrificial material may become a structural material by itsactual or effective encapsulation by other structural materials.Similarly, structural materials may be used to form sacrificialstructures that are separated from a desired structure during a releaseprocess via the sacrificial structures being only attached tosacrificial material or potentially by dissolution of the sacrificialstructures themselves using a process that is insufficient to reachstructural material that is intended to form part of a desiredstructure. It should be understood that in some embodiments, smallamounts of structural material may be removed, after or during releaseof sacrificial material. Such small amounts of structural material mayhave been inadvertently formed due to imperfections in the fabricationprocess or may result from the proper application of the process but mayresult in features that are less than optimal (e.g. layers with stairssteps in regions where smooth sloped surfaces are desired. In such casesthe volume of structural material removed is typically minusculecompared to the amount that is retained and thus such removal is ignoredwhen labeling materials as sacrificial or structural. Sacrificialmaterials are typically removed by a dissolution process, or the like,that destroys the geometric configuration of the sacrificial material asit existed on the build layers. In many embodiments, the sacrificialmaterial is a conductive material such as a metal. As will be discussedhereafter, masking materials though typically sacrificial in nature arenot termed sacrificial materials herein unless they meet the requireddefinition of sacrificial material.

“Supplemental sacrificial material” as used herein refers to a materialthat does not form part of the structure when the structure is put touse and is not added as part of the build layers but instead is added toa plurality of layers simultaneously (e.g. via one or more coatingoperations that applies the material, selectively or in a blanketfashion, to a one or more surfaces of a desired build structure that hasbeen released from an initial sacrificial material. This supplementalsacrificial material will remain in place for a period of time and/orduring the performance of certain post layer formation operations, e.g.to protect the structure that was released from a primary sacrificialmaterial, but will be removed prior to putting the structure to use.

“Primary sacrificial material” as used herein is a sacrificial materialthat is located on a given build layer and which is typically depositedor applied during the formation of that build layer and which makes upmore than 20% of the sacrificial material volume of the given buildlayer. In some embodiments, the primary sacrificial material may be thesame on each of a plurality of build layers or may be different ondifferent build layers. In some embodiments, a given primary sacrificialmaterial may be formed from two or more materials by the alloying ordiffusion of two or more materials to form a single material.

“Secondary sacrificial material” as used herein is a sacrificialmaterial that is located on a given build layer and is typicallydeposited or applied during the formation of the build layer but is nota primary sacrificial materials as it individually accounts for only asmall volume of the sacrificial material associated with the givenlayer. A secondary sacrificial material will account for less than 2.0%of the volume of the sacrificial material associated with the givenlayer. In some preferred embodiments, each secondary sacrificialmaterial may account for less than 10%, 5%, or even 2% of the volume ofthe sacrificial material associated with the given layer. Examples ofsecondary structural materials may include seed layer materials,adhesion layer materials, barrier layer materials (e.g. diffusionbarrier material), and the like. These secondary sacrificial materialsare typically applied to form coatings having thicknesses less than 2microns, 1 micron, 0.5 microns, or even 0.2 microns). The coatings maybe applied in a conformal or directional manner (e.g. via CVD, PVD,electroless deposition, or the like). Such coatings may be applied in ablanket manner or in a selective manner. Such coatings may be applied ina planar manner (e.g. over previously planarized layers of material) astaught in U.S. patent application Ser. No. 10/607,931, now U.S. Pat. No.7,239,219. In other embodiments, such coatings may be applied in anon-planar manner, for example, in openings in and over a patternedmasking material that has been applied to previously planarized layersof material as taught in U.S. patent application Ser. No. 10/841,383,now U.S. Pat. No. 7,195,989. These referenced applications areincorporated herein by reference as if set forth in full herein.

“Adhesion layer”, “seed layer”, “barrier layer”, and the like refer tocoatings of material that are thin in comparison to the layer thicknessand thus generally form secondary structural material portions orsacrificial material portions of some layers. Such coatings may beapplied uniformly over a previously formed build layer, they may beapplied over a portion of a previously formed build layer and overpatterned structural or sacrificial material existing on a current (i.e.partially formed) build layer so that a non-planar seed layer results,or they may be selectively applied to only certain locations on apreviously formed build layer. In the event such coatings arenon-selectively applied, selected portions may be removed (1) prior todepositing either a sacrificial material or structural material as partof a current layer or (2) prior to beginning formation of the next layeror they may remain in place through the layer build up process and thenetched away after formation of a plurality of build layers.

“Masking material” is a material that may be used as a tool in theprocess of forming a build layer but does not form part of that buildlayer. Masking material is typically a photopolymer or photoresistmaterial or other material that may be readily patterned. Maskingmaterial is typically a dielectric. Masking material, though typicallysacrificial in nature, is not a sacrificial material as the term is usedherein. Masking material is typically applied to a surface during theformation of a build layer for the purpose of allowing selectivedeposition, etching, or other treatment and is removed either during theprocess of forming that build layer or immediately after the formationof that build layer.

“Multilayer structures” are structures formed from multiple build layersof deposited or applied materials.

“Multilayer three-dimensional (or 3D or 3-D) structures” are MultilayerStructures that meet at least one of two criteria: (1) the structuralmaterial portion of at least two layers of which one has structuralmaterial portions that do not overlap structural material portions ofthe other.

“Complex multilayer three-dimensional (or 3D or 3-D) structures” aremultilayer three-dimensional structures formed from at least threelayers where a line may be defined that hypothetically extendsvertically through at least some portion of the build layers of thestructure will extend from structural material through sacrificialmaterial and back through structural material or will extend fromsacrificial material through structural material and back throughsacrificial material (these might be termed vertically complexmultilayer three-dimensional structures). Alternatively, complexmultilayer three-dimensional structures may be defined as multilayerthree-dimensional structures formed from at least two layers where aline may be defined that hypothetically extends horizontally through atleast some portion of a build layer of the structure that will extendfrom structural material through sacrificial material and back throughstructural material or will extend from sacrificial material throughstructural material and back through sacrificial material (these mightbe termed horizontally complex multilayer three-dimensional structures).Worded another way, in complex multilayer three-dimensional structures,a vertically or horizontally extending hypothetical line will extendfrom one or structural material or void (when the sacrificial materialis removed) to the other of void or structural material and then back tostructural material or void as the line is traversed along at least aportion of the line.

“Moderately complex multilayer three-dimensional (or 3D or 3-D)structures are complex multilayer 3D structures for which thealternating of void and structure or structure and void not only existsalong one of a vertically or horizontally extending line but along linesextending both vertically and horizontally.

“Highly complex multilayer (or 3D or 3-D) structures are complexmultilayer 3D structures for which the structure-to-void-to-structure orvoid-to-structure-to-void alternating occurs once along the line butoccurs a plurality of times along a definable horizontally or verticallyextending line.

“Up-facing feature” is an element dictated by the cross-sectional datafor a given build layer “n” and a next build layer “n+1” that is to beformed from a given material that exists on the build layer “n” but doesnot exist on the immediately succeeding build layer “n+1”. Forconvenience the term “up-facing feature” will apply to such featuresregardless of the build orientation.

“Down-facing feature” is an element dictated by the cross-sectional datafor a given build layer “n” and a preceding build layer “n−1” that is tobe formed from a given material that exists on build layer “n” but doesnot exist on the immediately preceding build layer “n−1”. As withup-facing features, the term “down-facing feature” shall apply to suchfeatures regardless of the actual build orientation.

“Continuing region” is the portion of a given build layer “n” that isdictated by the cross-sectional data for the given build layer “n”, anext build layer “n+1” and a preceding build layer “n−1” that is neitherup-facing nor down-facing for the build layer “n”.

“Minimum feature size” refers to a necessary or desirable spacingbetween structural material elements on a given layer that are to remaindistinct in the final device configuration. If the minimum feature sizeis not maintained on a given layer, the fabrication process may resultin structural material inadvertently bridging the two structuralelements due to masking material failure or failure to appropriatelyfill voids with sacrificial material during formation of the given layersuch that during formation of a subsequent layer structural materialinadvertently fills the void. More care during fabrication can lead to areduction in minimum feature size or a willingness to accept greaterlosses in productivity can result in a decrease in the minimum featuresize. However, during fabrication for a given set of process parameters,inspection diligence, and yield (successful level of production) aminimum design feature size is set in one way or another. The abovedescribed minimum feature size may more appropriately be termed minimumfeature size of sacrificial material regions. Conversely a minimumfeature size for structure material regions (minimum width or length ofstructural material elements) may be specified. Depending on thefabrication method and order of deposition of structural material andsacrificial material, the two types of minimum feature sizes may bedifferent. In practice, for example, using electrochemical fabricationmethods and described herein, the minimum features size on a given layermay be roughly set to a value that approximates the layer thickness usedto form the layer and it may be considered the same for both structuraland sacrificial material widths and lengths. In some more rigorouslyimplemented processes, examination regiments, and rework requirements,it may be set to an amount that is 80%, 50%, or even 30% of the layerthickness. Other values or methods of setting minimum feature sizes maybe set.

“Sublayer” as used herein refers to a portion of a build layer thattypically includes the full lateral extents of that build layer but onlya portion of its height. A sublayer is usually a vertical portion ofbuild layer that undergoes independent processing compared to anothersublayer of that build layer.

Tissue Shredding Devices, Methods for Making and Methods for Using

FIGS. 5-7 illustrate an exemplary embodiment of a working end of atissue removal device which can be fabricated wholly or in part byelectrochemical fabrication techniques, such as those described orreferenced herein. Tissue removal device working end 100 has a distalregion “D” and proximal region “P,” and includes housing 101 and bladestacks 102 and 104. Blade stacks 102 and 104 include a plurality ofblades 102A-102C and 104A-104C, respectively. Three blades are shown ineach stack, although the blade stacks can have one or more blades. Eachof the blades includes a plurality of teeth 106 (see FIG. 7), some ofwhich are shown projecting from housing 101 and configured to engage andprocess tissue. Processing tissue as used herein includes any of cuttingtissue, shredding tissue, capturing tissue, any other manipulation oftissue as described herein, or any combination thereof. The working endof the device generally has a length L, height H, and width W. Housing101 can have a variety of shapes or configurations, including agenerally cylindrical shape.

In this embodiment both blade stacks are configured to rotate. Theblades in blade stack 102 are configured to rotate in a directionopposite that of the blades in blade stack 104, as designated by thecounterclockwise “CCW” and clockwise “CW” directions in FIG. 5. Theoppositely rotating blades direct material, such as tissue, into aninterior region of housing 101 (described in more detail below). In someembodiments, the blades can be made to rotated in directions opposite tothose indicated, e.g. to disengage from tissue if a jam occurs or tocause the device to be pulled distally into a body of tissue when givenappropriate back side teeth configurations.

Housing 101 also includes a drive mechanism coupler 105, shown as asquare hole or bore, which couples a drive train disposed in the housingto a drive mechanism disposed external to the housing. The drivemechanism, described in more detail below, drives the rotation of thedrive train, which drives the rotation of the blades. The drive traindisposed in the housing can also be considered part of the drivemechanism when viewed from the perspective of the blades. Drivemechanism coupler 105 translates a rotational force applied to thecoupler by the drive mechanism (not shown) to the drive train disposedwithin housing 101.

FIG. 5 also shows release holes 111-115 which allow for removal ofsacrificed material during formation of the working end.

FIG. 6 shows a perspective view of the proximal end of tissue removaldevice working end 100. Material directed into housing 101 by therotating blades is directed into chamber 103, wherein it can be storedtemporarily or directed further proximally, as described below. A firstgear train cover 121 provides for a first surface of chamber 103, whilea second gear train cover 122 provides a second surface of chamber 103.FIG. 6 also shows drive mechanism coupler cover 123.

In some embodiments in which the working end 100 includes a storagechamber, the chamber may remain open while in other embodiments it maybe closed while in still other embodiments it may include a filter thatonly allows passage of items of a sufficiently small size to exit.

FIG. 7 shows a perspective view of the distal end of the working end100. In this embodiment the blades in stack 102 are interdigitated withthe blades in stack 104 (i.e. the blade ends are offset vertically alongdimension H and over have maximum radial extensions that overlaplaterally along the width dimension W. The blades can be formed to beinterdigitated by, e.g. if formed using a multi-layer, multi-materialelectrochemical fabrication technique, forming each blade in stack 102in a different layer than each blade in stack 104. If during formationportions of separately moveable blade components overlap laterally theoverlapping blade must not just be formed on different layers but formedsuch an intermediate layer defined a vertical gap between them. Forexample, the bottom blade in stack 102 is shown formed in a layerbeneath the layer in which the bottom blade in stack 104 is formed.

FIG. 8 illustrates a perspective view of an exemplary gear train systemwhich can be included in any suitable working end described herein todrive the rotation of the blades (such as the embodiment of the workingend shown in FIGS. 5-7). The gear train system includes drive mechanismcoupler 105 at a first end of the gear train which is coupled to gear131A in first gear train 131, and is coupled to gear 141A in gear train141. Coupler 105, in response to a rotational force applied via arotating pin (not shown) which may be considered part of the drivemechanism or a separate component of the device, drives the gears infirst gear train 131 and the gears in the second gear train 141, whichdrives the respectively coupled blade stacks to rotate in oppositedirections. Gears 131D and 141E are coupled to blade stack shafts, whichallow the gear trains to drive the rotation of the blades. Gear trains131 and 141 include gears 131A-131D and 141A-141E, respectively. Byhaving an odd number of gears in one gear train and an even number ofgears in the other gear train, the blades will rotate in oppositedirections. The arrows in FIG. 8 show the direction of forward rotationof the gears and the blades.

A potential challenge when fabricating parts or components of a deviceusing a multi-layer multi-material electrochemical fabrication processor other similar process can be creating very small gaps, or spaces,between components of the device. Potential challenges are describedabove in the “Minimum feature size” definition section. In someembodiments the gears are formed using an electrochemical fabricationprocess or other similar process and are formed in a singlemulti-material layer. One challenge in forming micro-gears in thismanner can be making sure the gaps between teeth on adjacent gears (i.e.meshing gears) can be formed consistently and with appropriatedimensions. For example, FIG. 9 shows a portion of two adjacent gears G1and G2 formed from a multi-layer, multi-material electrochemicalfabrication process. The gears are formed in this configuration, suchthat at least one tooth on one of the gears is formed “in-between” twoteeth on the adjacent gear. Gear G1 includes teeth G1 a and G1 b andgear G2 includes teeth G2 a and G2 b. During the fabrication process,gaps “g,” formed between structural material depositions of the teeth ofgear G1 and gear G2 must be large enough to meet an associated minimumfeature size while still providing a desired engagement with teeth ofthe adjacent gear so that a backlash is not excessive and so thatbinding of the gears does not occur due to either lateral shifting ofgears as a result of lateral shifting of their axles within theirengagement holes or canting or tilting of the gears relative to oneanother as a result of out of movement that may be allowed by thespacing between the gear shafts and their guide holes.

FIG. 10 illustrates an exemplary embodiment of a first gearconfiguration for assembled fabrication which allows for minimizingbacklash while still meeting minimum feature size limitations in bothgear tooth spacing as well as axle shaft and guide hole, bearing orbushing spacing. Each gear is formed from more than one layer ofmaterial rather than one layer of material. Each gear “layer” may bereferred herein as a “tier.” Driving gear 161 includes upper tier 162,lower tier 165, and intermediate tier 166. Intermediate tier is formedas a separate layer and is between upper tier 162 and lower tier 165.Upper tier 162 includes tooth 164 and lower tier 165 includes tooth 163.Six teeth are shown on the upper and lower tiers, while there are noteeth on the intermediate tier. Driven gear 151 is formed in the samemanner as driving gear 161 and includes upper tier 156 including tooth153, lower tier 155 including tooth 152, and intermediate tier 154. Sixteeth are shown on the upper and lower tiers in driven gear 151, whilethere are no teeth on intermediate tier 153.

The teeth on gears 161 and 151 mesh properly and behave may behave, forexample, as an involute spur gears. In operation, tooth 164 of uppertier 162 of driving gear 161 contacts and drives tooth 153 on the uppertier 156 of driven gear 151. Tooth 163 on lower tier 165 of driving gear161 contacts and drives tooth 152 on lower tier 155 of driven gear 151.

In some embodiments, the teeth are formed such that as the gears turnthere are always two consecutive teeth on the driving gear on differenttiers (e.g., tooth 164 and tooth 163 of driving gear 161) that are incontact with two consecutive teeth on the driven gear (e.g. tooth 153and tooth 152 on driven gear 151). The gears can be fabricated such thatthe distance, or gap dimension, between consecutive teeth on a singletier is maximized, which may be beneficial if the gap size would havebeen too small for fabrication if all gear teeth were on a single tierinstead of split between different tears.

It is possible to drive the gear train in both directions. In someembodiments, additional tiers with teeth may be incorporated into thegears so that gear interfaces (i.e., contact between teeth on adjacentgears) do not occur on merely two levels but rather occur on three ormore levels.

FIGS. 11 and 12 show three gears in an “as fabricated” configuration.FIG. 11 is a top view of gear 170, gear 173, and gear 174. Gear 170includes tooth 171 and tooth 172 on its upper tier, separated bydistance, or gap, “gb.” Gear 173 includes tooth 175 and 176 on its uppertier. Teeth 175 and 176 are fabricated separated on either side of tooth172 of gear 170 by a distance, or gap, “gs.” By using a multi-tieredgear, the distance gs between the teeth on adjacent gears is larger thanif the teeth on gears 170 and 173 were on a single tier. FIG. 12 shows across-sectional perspective view of the three gears from FIG. 11,illustrating upper tier 177 and lower tier 178 which are separated by anintermediate tier 179 without teeth that may be relatively thin (e.g. ½,⅕, 1/10, or even 1/20 or less of the thickness of the upper and lowertiers). These intermediate tiers allow a lower tiered tooth on one gearto be fabricated under an upper tier tooth such that they partially orcompletely laterally (i.e. within the dimensions the layers, e.g. XYdimensions, relative to the axis of stacking of the layers, e.g. the Zdimension) overlap without causing layer-to-layer adhesion of the teethdue to the presence of an intermediate volume of sacrificial materiallocated vertically between them. Forming gears with multiple tiers,allows for intra-layer gaps between teeth of adjacent gears (i.e,engaging gears) to remain above a minimum feature size while allowingeffective gaps between engaging gears as a Whole to have a much smallertooth gap or tighter tooth pitch. In some embodiments, the existence ofintermediate non-toothed tiers allows tighter teeth spacing and/or widerteeth dimensions without needing to resort to gears with more than twotoothed tiers. Multi-tier gears as set forth in the example, provide anengage method and components for forming tightly-meshed teeth whileallowing necessary gaps to be reliably formed between teeth on adjacentgears. In some embodiments, each tier may be formed from a singlemulti-material layer, while in other embodiments each tier may be formedfrom a plurality of multi-material layers.

In embodiments in which a gear has more than one tier, and it may bepossible to remove one or more of the immediate tiers (i.e, those thatdo not have gear teeth) as it may be possible to form gear teeth onmultiple levels without any two consecutive levels having teeth thatoverlap in the X-Y plane in the as formed position.

FIGS. 13 and 14 highlight the proximal end and distal end, respectively,of the gear trains shown in FIG. 8, which incorporate a multi-tieredgear design. Gear 131A is comprised of a first tier 131A1 and a secondtier 131A2, each having six teeth. Rotation of gear 131A due torotational threes on the drive mechanism coupler 105 causes the teeth ontier 131A1 to contact and drive the teeth on tier 131B1 of gear 131B,while teeth on tier 131A2 engage teeth on tier 131B2. The gears in geartrain 141 also include multi-tiered or multi-layered gears and functionin the same way. FIG. 14 illustrates the distal end of the gear train,illustrating gear 131C comprising tier 131C1, which is configured torotate and engage with tier 131D1 of gear 131D, and tier 131C2, which isconfigured to rotate and engage with tier 131D2 of gear 131D. Rotationof gear 131D rotates the blades in blade stack 102 about a blade shaft(not shown).

FIG. 15 illustrates an alternative embodiment of a gear formation thatcan be used in any of the tissue removal devices herein. The drive trainincludes driving gear 180, gear 184, and gear 188 formed by an EFABprocess in the configuration shown. In this embodiment the gears arecomprised of multiple tiers, but not all of the teeth alternate amongsttiers as in the embodiment in FIGS. 8-14. In this embodiment only theteeth that are near teeth on an adjacent gear in the “as-fabricated”configuration are formed in only one tier, while the remaining teeth onthe gears are formed in all tier layers. In terms of teeth height, theteeth that are near teeth on an adjacent gear during formation have ashorter height (with height being measured in the layer stackingdirection and the gears being formed with their planes lying in theplanes of the layers) than the other teeth on the gear. In reference toFIG. 15, driving gear 180 includes an upper tier and a lower tier,wherein the nine teeth 195 (only three of which are labeled) are threelayers (or tiers) thick (i,e. upper, lower, and intermediate tiers).Teeth 181, 182, and 183 are each only one layer thick, with teeth 182and 183 formed only in the lower tier, and tooth 181 is formed only inthe upper tier. Gear 184 is formed in a similar manner, with all of theteeth except for teeth 185, 186, 187, 189, 190, and 193 formed in boththe upper and lower tiers. Teeth 185, 187, 189, and 190 are formed onlyin the upper tier, and teeth 186 and 193 are formed only in the lowertier. Gear 188 is formed in the same manner as 180. In use, when drivinggear 180 is rotated (e.g., in a clockwise direction), tooth 182 contactstooth 186 on gear 184, and the first tooth 195 on gear 180 contactstooth 185 on gear 184. As gear 180 continues to rotate after almost afull revolution, lower tier tooth 183 on gear 180 contacts lower tiertooth 193 on gear 184, and upper tier tooth 181 contacts upper tiertooth 190 on gear 184.

Because teeth 195 and 196 on gears 180 and 184, respectively, are formedon multiple layers and therefore have a greater height than a toothformed on a single layer, they may be better able to make solid contactwith one another and more effectively turn the gear. It may bebeneficial to fabricate the teeth in such a manner if forming the teethon only one tier prevents the gear from turning effectively because theheight of teeth formed from a single layer of material is too small, andadequate contact is not being made between the teeth as the gearsrotate. An exemplary advantage of this design can allow for gaps to becreated that are of a large enough size while providing for bettercontact between gear teeth.

FIGS. 16-19 illustrate yet another alternative gear train design whichmay allow meeting minimum feature size requirements while providing morerobust gears along with back lash not being excessively large. FIG. 16shows driving gears 220, 221, and 222 in their as-formed configuration.Teeth 223 and 224 on gear 220, teeth 225, 226, 228 and 230 on gear 221,and teeth 227 and 229 on gear 222, are formed such that each tooth isnotched (i.e. a segment of each tooth is removed from one of the upperor lower tier and from the intermediate tier. Each of these teeth have aportion that is sacrificed to allow assembled formation of the all ofthe components (gears 220, 221, and 222) during the formation process.Sacrificing a portion of the each of these teeth allows for anintra-layer gap to be created between teeth (i.e., between teeth 223 and225, 224 and 226, 227 and 228, and 229 and 230) to be larger than theminimum feature size while allowing a tighter gear engagement with eachtooth being stronger and significantly more rigid that it was in eitherof the previous two embodiments. One method of sacrificing a portion ofthe tooth is to create each gear from three tiers (e.g. layers) ofmaterial, and forming the tooth so that the notched portion of selectedgears is formed as a single tier thickness (e.g. a single layerthickness). All of most of the teeth are three tiers thick while only asmall portion of the notched teeth are not three tiers. As noted abovetooth 223 includes portion 231, however, that is only 1 tier thick.Teeth 224, 225, 226, 227, 228, 229, and 230 also each have a portionthat is only 1 layer thick. Teeth 225, 226, 227, and 229 have portionssacrificed that cannot be seen in FIG. 16, but have positions on theteeth that allow formation of the underling teeth from the mating gearsto be formed without causing inadvertent gear bonding or welding. Bycreating a portion of a tooth that is only 1 tier thick, more intralayerspace can be created between the teeth, which can be beneficial in thefabrication process. FIG. 17 illustrates a partial perspective view ofthe three gears from FIG. 16 in their “as fabricated” configuration.

FIG. 18 shows the gears from FIGS. 16 and 17 showing the direction ofrotation as illustrated by the arrows where gear 220 is the driving gearand gears 221 and 222 are being driven. FIG. 18 also shows contactspoints 240 between the teeth. FIG. 19 shows a magnified view of contactpoints 240 between the driving and driven teeth. As shown, the portionof the tooth that is sacrificed is preferably on edge of the gear thatis opposite the side of the gears that do the driving or are beingdriven during the forward or high torque operation of the gear train.

The gear trains described above allow a drive mechanism, examples ofwhich are described above and below, to be at a distance from the bladessuch that the distal end of the working end can be advanced into contactwith tissue in an unobstructed manner.

In some alternative embodiments the all or portions of the gear train(s)can be replaced with one or more sprockets and one or more chains todrive the blades, one or more pulley and belts, one or more fluid flowpaths and turbine blades, or the like.

When manufacturing tissue removal devices of the various embodiments setforth herein using a multi-layer multi-material electrochemicalfabrication process, it is generally beneficial if not necessary tomaintain horizontal spacing of component features and widths ofcomponent dimensions remain above the minimum feature size. It isimportant that vertical gaps of appropriate size be formed betweenseparately movable components that overlap in X-Y space (assuming thelayers during formation are being stacked along the Z axis) so that theydo not inadvertently bond together and to ensure that adequate pathwaysare provided to allow etching of sacrificial material to occur. Forexample, it is generally important that gaps exist between a gearelement (e.g. a tooth) in a first gear tier and a second gear tier sothat the overlapping teeth of adjacent gears do not bond together. It isalso generally important to form gaps between components that moverelative to one another (e.g., gears and gear covers 121 and 122 (seeFIG. 20), between blades and housing 101, etc.). In some embodiments thegaps formed between moving layers is between about 2 um and about 8 um.

FIG. 20 illustrates a partial view of the working end of tissue removaldevice in which the top portion and one side wall of housing 101 havebeen removed to show one of the exemplary gear trains from FIG. 8disposed in housing 101. Gear enclosure or cover 121 encloses the firstgear train 141 (not shown) and provides a lower surface, in combinationwith the inside of housing 101, for chamber 103. FIG. 21 shows aperspective cross-sectional view of the device of FIG. 20, includingsecond gear train cover 122 wherein the cross-sectional cut sectionsgears 131B and 141C each in their as fabricated positions wherein gapsformed from sacrificial material laterally located on intervening layersexist between upper and lower surfaces of these gears and thecorresponding lower surfaces of covers 122 and 121 and upper surfaces ofthe lower portions of housing 101. The gear train covers 121 and 122extend from the proximal end of the device to a point just proximal tothe blades, and have distal ends which are rounded to accommodate therotation of the blades while preventing as much tissue as possible fromentering the gear train assembly. An exemplary function of gear covers121 and 122 is to prevent material which is directed into chamber 103from getting caught in the gears and preventing continued rotation ofthe blades. FIG. 21 also illustrates the section of gear 141-C exposesshaft 142-C around which gear 141-C rotates via a circular gaps (e.g.having an intralayer radial width greater than the minimum featuresize). Also FIG. 21 illustrates that when gears 131B and 141C are intheir as formed positions, they have etching holes 112-B and 114-Brespectively that are aligned with etching holes 112-A and 114-A inhousing 101 that allow more direct entry of etchant into the gearmovement cavities defined by covers 122 and 121 in conjunction withhousing 101 so that post-layer formation etching of sacrificial materialcan more readily occur from these cavities. In some embodiments partialalignment would be better than no alignment and offset of etching holesby no more than 2 mm or even 5 mm would be beneficial as compared tooffsets which are significantly greater. FIG. 21 also shows a portion ofblade shaft 103 around which blade stack 104 rotates. FIG. 21 along withFIG. 5 also shows interdigitated fingers 107 which are located betweensuccessive blade levels to inhibit the outflow of tissue drawing intocavity 103 as the blades tips rotate out of and then back into thehousing. Such fingers, vacuum (i.e. suction applied to the proximal endof the working end), irrigation directed onto the blades within thehousing (e.g. vertically downward or downward and proximally), or acombination of two or more of these elements may be useful in removingtissue from the blade and inhibiting its distal exit from the workingend back into working area within the body of a patient. In someembodiments, it is desired to define a Shearing thickness as the gapbetween elements has they move past one another. Such gaps may bedefined by layer thickness increments or multiple such increment or bythe intralayer spacing of elements as they move past one another. Insome embodiments, shearing thickness of blades passing blades or bladesmoving past interdigitated fingers, or the like may be optimally set inthe range of 2-100 microns or some other amount depending on theviscosity or other parameters of the materials being encounter and whatthe interaction is to be (e.g. tearing, shredding, transporting, or thelike). For example for shredding or tearing the gap may be in the rangeof 2-10 microns and more preferably in the range of 4-6 microns.

As described in the embodiments above, the working end includes a drivemechanism coupler 105 that is configured to be coupled to a drivemechanism which translates a rotational force to rotation of the firstset of gears in each of the gear trains. For example, as shown in FIG.5, drive mechanism coupler 105 has a square configuration and is adaptedto receive a square drive pin (not shown), wherein the pin is part of adrive mechanism which translates a rotational force to rotation of thegears in the train. FIG. 22 illustrates an alternative drive mechanismcoupler 250 with a D-shaped hole, or bore, 251, which is adapted toreceive D-shaped element 253 which can be engaged with a chain, a belt,a fluid flow, an electrical motor, a flexible drive shaft, bevel gear,crown gear, a spur gear, linear gear, or the like which can undergo amotive force to cause a desired rotation of the drive chain and bladesto power the device. The shaped element may be part of a pin or otherelement which allows appropriate engagement. The cross sectional shapeof the drive bore and pin can also be almost any other cross-sectionalshape which can drive the gear train, for example, a hexagonal shape,oval, elliptical, etc.

FIGS. 23A-27C illustrate alternative exemplary embodiments of drivemechanisms which can power the drive trains in the working end, any ofwhich may be adapted to be included in any suitable tissue removaldevice, such as those described herein. To position the working end at adesired location in the patient, the working end can be advanced to thetarget site within a delivery member (e.g., cannula, catheter, sheath,etc.). A portion of the device, e.g. the working end or the working endin combination with a single or multi-port catheter can also be adaptedto be advanced over a guide wire. In some embodiments, the tissueremoval device is coupled to an elongate introducer which is used toadvance the working end of the tissue removal device to the targettissue site through a delivery member. In some embodiments, the drivemechanism, or at least a portion thereof, is disposed within theintroducer. An example delivery systems are described in more detailbelow.

FIGS. 23A-23D illustrate a first embodiment of the working end and drivesystem of a device in which the drive mechanism includes a belt andpulley. FIG. 23A shows a portion of housing 270, tissue processingelements 271, a portion of gear train 276, belt 272, and pulley 273.FIG. 23B shows a sectional view including belt 272 and a portion ofpulley 273 disposed in housing 270. FIG. 23C shows the housing 270without the belt. FIG. 23D shows a sectional view of housing 270including a portion of pulley 273, drive mechanism coupler 275, andoptional guide wire lumen 274 disposed on the bottom of housing 270.Actuating the belt as shown by the arrows in FIGS. 23A and 23B causespulley 273 to rotate due to frictional forces between the belt andpulley. The pulley includes a protruding pin (not shown) which coupleswith drive mechanism coupler 275 to drive the gear train. Rotation ofthe pulley 273 drives the gear trains which activates the tissueprocessing elements 271. In some embodiments the belt is a nitinol wirebut can be any other suitable material. In other embodiments, the smoothbelt and pulley may be replaced with a chain and sprocket or with aminiature toothed pulley and toothed belt. In some embodiments, thepulley and belt he controlled, at times, to drive the tissue processingelements in the opposite direction to that indicated.

FIGS. 24A-C illustrate a second embodiment of the working end and drivesystem of a device in which the drive mechanism is a hydraulic drivemechanism. FIG. 24A shows a portion of the device including a portion ofhousing 280, tissue processing elements 283, turbine 281 with aplurality of blades 287 coupled to a driving pin (not shown in FIG.24A), wherein turbine 281 is coupled to drive mechanism coupler 282 viathe pin. FIG. 24B is a sectional view of housing 280 in which turbine281 is disposed. Housing 280 includes fluid channel 288 through whichfluid (e.g., liquid or gas) flows in the direction of arrow 284,rotating turbine 281. The fluid exits the housing in the direction ofarrow 285 through fluid channel 289. The fluid rotates the blades 287 ofturbine 281, which drives the gear train, which activates the tissueprocessing elements 283. A pump disposed proximal to the housing (e.g.outside the body of the patient and connected to the working end bylumens within a multi-port catheter) and can be used to control the flowof fluid into the housing. In some embodiments, the pump and otherelements in the fluid flow path may be configured to allow reversedoperation of the device when desired.

In the embodiments above the tissue removal, or processing, elements andthe housing of the working end are configured such that the tissueremoval elements can remove tissue which is located distal to theworking end. The tissue removal elements can also be, however, disposedat other locations within the working end. In some embodiments they aredisposed so that they can remove tissue along one or more sides of thehousing. In some uses the device may be advanced in a distal direction,yet the tissue which is to be removed is located along the sides of thedevice. As will be described in more detail below, it may beadvantageous to protect certain tissue from being damaged while removingother tissue. Positioning the blades in the working end in specificlocations can be one way to do this.

FIGS. 25A-25G illustrate an example a of a side tissue removal workingend. FIG. 25A is a top sectional view with a top portion of the housingremoved, which shows working end 290 comprising housing 298 and fourtissue removal elements 294-297, which are shown as blade stacks. Bladestacks 294 and 295 process tissue along one side of the housing bydirecting tissue in the direction of arrow 292. Blade stacks 296 and 297process tissue along a second side of the housing by directing tissue inthe direction of arrow 293. As shown in FIGS. 25A-B, blade stacks 294and 297 each have two blades, while blade stacks 295 and 296 each havethree blades. FIG. 25C shows a perspective view without housing 298illustrating the drive mechanism for the side tissue removal device 290.The drive mechanism includes belt 299, distal pulley 300, and sidepulleys 301-304. The side pulleys are coupled to the blade stacks androtation of the side pulleys rotates the blade stacks. The belt isdisposed through side pulleys 301 and 302 and around distal pulley 300before returning through side pulleys 303 and 304. Actuating of belt 299therefore activates all four blade stacks. In some embodiments the beltis a nitinol wire, but can be any other suitable material. FIG. 25D is aview with the top portion of the housing removed to show the internaldrive mechanism. FIG. 25E shows the same view with the top on thehousing. FIGS. 25F and 25G show top views of the working end shown inFIGS. 25D and 25E, respectively. In still embodiment, as well as in theother embodiments, set forth herein, vacuum, irrigation, or acombination of the two may be used to send extracted tissue from theinterior of the working end, proximally to a storage reservoir (e.g.within the working end or located outside the body of the patient onwhich a procedure is being performed).

FIGS. 26A-26F illustrate an alternative hydraulic or pneumatic drivemechanism for a side tissue removal working end. FIG. 26A shows thedevice 310 including housing 311 and tissue removal elements on a firstside 312 of device 310. FIG. 26B illustrates housing 311 with a topportion removed to reveal inside the housing. The housing includes fluidchannels which allows fluid to flow into the housing in the direction ofarrows 313 and 314. The fluid turns the blades of turbines 316 and 318,which rotates the turbines shafts, which are coupled to the tissueremoval elements. Guides 315 helps direct the flow of fluid to ensurethe blades of the turbines rotate in the proper direction to cause thetissue removal elements to rotate inward. The fluid continues past theturbines and drops through opening 320. The fluid exits through hole 321(see FIG. 26E) and out of housing in the direction of arrow 319. Theexiting fluid can also help direct tissue in the proximal direction awayfrom the working end. FIG. 26C shows a top view of the device shown inFIG. 26B. FIG. 26D shows the turbines each coupled to one blade stack.FIG. 26E is a sectional perspective view, showing fluid inlet 313,blades 317 of the turbine and a portion of the tissue removal elements.FIG. 26F shows a side sectional view of the view shown in FIG. 26E,including blade shaft 322.

FIGS. 27A-27C illustrate an alternative drive mechanism. FIG. 27Aillustrates tissue removal device 300 including working end 301 andintroducer 302. Working end 301 includes distally facing tissue shredderelements 303. FIG. 27B and 27C illustrate the drive mechanism with asectional perspective view and a partial top view. The drive mechanismincludes tube 304 (disposed within introducer 302) with gear teeth 305cut circumferentially, which can be seen more clearly in FIG. 27C. Whenrotated, the teeth 305 on tube 304 contact and drive teeth 307 on gear306, the axis of rotation of which is substantially orthogonal to theaxis of rotation of tube 304. Pin 308 (shown with a square crosssectional shape) is engaged with a square hole in gear 306 and with asquare hole in drive mechanism coupler 312 in the working end. Rotationof gear 306 therefore rotates pin 308, which rotates the drive mechanismcoupler 312, which drives the gear trains (which can be partially seenin FIG. 12) within the working end. FIG. 27C also shows an exemplarycoupling 311 between a distal end of introducer 302 and housing 310 ofworking end 301.

The tissue removal device as shown in FIGS. 27A-C can also provideirrigation to the working end to provide for maximum suction by avacuum, which is used to remove tissue from the working end. Irrigationfluid can be delivered between inner tube 304 and the inner diameter ofintroducer tube 302. The irrigation as well as debris is then pulledproximally by suction through the lumen of inner tube 304 in thedirection of the arrow shown in the figure. Irrigating helps maximizethe suction by ensuring that the volume on the inner tube 304 is full ofboth tissue and irrigating fluid. The irrigating fluid forced distallybetween the introducer and inner tube 304 can also be directed into theworking end to provide irrigation to the working end.

In variations of the above noted embodiments the drive mechanism can beconfigured to include one or more sprockets and one or more chains.

In some alternative embodiments the drive mechanism which extendsthrough an introducer may extend a significant distant from the drivemechanism coupler (e.g. perpendicular to the plane of the upper or lowerfaces of the housing, i.e. in the Z-direction or vertical directionrelative to the planes of the layers (e.g. horizontal planes) used informing the device via multi-layer, multi-material electrochemicalfabrication methods. In other alternative embodiments the drivemechanism may be coupled to a secondary shaft or flexible lead whichextends in a direction parallel to the planes of the faces of thehousing (e.g. proximally along the longitudinal axis of the device orradially relative to the longitudinal axis of the device).

In some embodiments the drive mechanism includes universal joints, crowngears, or bevel gears coupled to drive gears and oriented so the drivetrain axis may be rotated to become parallel to the longitudinal axis ofthe device, or to otherwise lie perpendicular to the height of thedevice. In some embodiments some gears in a gear train may be formed inthe same orientation as other gears in the train, but then rotated onbendable supports or pivotable supports to take on a desiredorientation.

The working ends of the tissue removal devices described herein can beused to remove tissue from a subject. The tissue to be removed isgenerally referred to herein as “target tissue”, and the generallocation at which the working end is positioned to remove the targettissue is generally referred to herein as the target tissue “site.” Theworking end can be configured for use in a variety of types of medicalprocedures. For example without limitation, the working end can beconfigured for use in traditional open surgical procedures or minimallyinvasive procedures (i.e., any procedure less invasive than opensurgery, such as percutaneous procedures).

When the working end is used in some minimally invasive procedures, itis coupled to a elongate member of a delivery system so that the workingend can be positioned at the target tissue site. FIG. 28 illustrates anexemplary coupling 322 between introducer 321 and working end 320,wherein the introducer is adapted to introduce, or position, the workingend at the target tissue site. As shown, introducer 321 is coupled tothe proximal end of the working end 320, but the introducer need notnecessarily be coupled to the proximal end of the working end 320, butcan be coupled to a general proximal region of working end 320. In someembodiments the coupling between introducer 321 and working end 320 isperformed after the fabrication of working end 320, or after partialfabrication of working 320. Coupling 322 can take on a variety of forms,such as, without limitation, a lap joint, as is the exemplary coupling311 shown in FIG. 27C. Introducer 321 can have one or more lumens 323(only one shown) which are in communication with the chamber within theworking end (not shown). The lumen(s) of the introducer can house any orall of the drive mechanism components, irrigation system, aspirationsystem, etc. As shown in FIG. 28, the proximal end 325 of housing 326and the distal end of introducer 321 have substantially similarcross-sectional shapes (shown as generally circular), which may make iteasier to couple the working end to an introducer. The introducergenerally extends proximally from the working end and may have aproximal end adapted to be disposed external to the subject. In someembodiments the introducer is a stiff rigid element, while in someembodiments it is a torsionally stiff and flexible element. FIG. 29illustrates an exemplary articulatable introducer 330 includingnon-articulating portion 331 and articulating portion 332, wherein theintroducer is coupled to working end 333. The entire introducer may alsobe articulatable, or there may be alternating portions of articulatableand non-articulatable portions of the introducer. For some procedures itmay be known where the introducer is likely to need to bend orarticulate, and only this portion of the introducer may be configured toarticulate. The articulating segments can be articulated with deliverysystem actuators as described below.

Depending on the medical procedure, the introducer can be coupled to theworking end to advance the working end to the target tissue site througha delivery member such as, without limitation, a cannula, trocar,catheter, sheath, etc. FIG. 30 shows introducer 336 and working end 337,including shredders 338, coupled together, with a portion of introducerdisposed within delivery member 335. The introducer/working end assemblycan be moved axially relative to the delivery member by distallyadvancing the introducer and/or proximally withdrawing the deliverymember.

The working end of the device may be adapted with a lumen or bore toincorporate additional delivery system components that can be movedaxially relative to the fixed shredders within the working end. FIG. 31Aillustrates a portion of housing 339 of the working end, including fixedtissue removal elements 340, optional irrigation port 342, and slidableelement 341 disposed within a bore in housing 339. The slidable element341 can be actuated axially (i.e., distally or proximally) as shown bythe directions of the arrows using an actuator in the deliveryhand-piece or other mechanism that allows for user control. In someembodiments the introducer can have a separate lumen for the slidableelement which is aligned with the slidable element bore or lumen in theworking end.

In some embodiments the working end housing is configured with more thanone bore (the introducer can similarly have one or more lumens) toenable it to receive more than one axially movable element, which canenable more delivery tools to access the target tissue site morequickly. In some embodiments the slidable, or axially movable, elements,can be visualization tools such as a camera or an illumination tool.Focus on the target tissue can be maintained before and during theprocedure by being able to move visualization tools in this manner. Insome embodiments irrigation and/or suction tools are slidable elements.In use, a slidable element may also be configured to be retractedcompletely from the introducer/working end assembly to allow for adifferent element to be advanced to the distal end of the housing.

FIG. 31B shows an exemplary embodiment of working end 600 that isadapted to be actuated to rotate working end 600 relative to introducer602. Working end 600 pivots through drive pin 601, and actuation wires603 are coupled to working end 600 at attachment points 604. Actuationof wires 603 causes rotation of working end 600 relative to introducer602.

FIGS. 32A-32C illustrate a device and methods for providing a space forvisualization of the target site, and/or target tissue. Creating a spacein front of the tissue removal elements allows for visualization of theworking area during and after tissue removal. FIG. 32A illustrates afirst embodiment in which working end 350 includes retractable shredders351. Inflated balloon 352 is inflated in the direction of tissue that isto be removed to create a space for visualization. In one embodiment theinflatable balloon is disposed at the distal end of an axially slidableelement which is advanced to the working area through the working end ofthe device. An inflation fluid (e.g., gas, liquid) is then pumpedthrough the lumen of the slidable element into the balloon to expand theballoon. The working end also includes an optical device 353 (e.g., acamera) which can be a separate slidable element, which is distallyadvanced towards the working area to visualize the working area. Theballoon can then be deflated and retracted back into the working end.The camera is similarly retracted into the working end. The tissueremoval elements can be retractable to avoid puncturing the balloon withthe tissue removal elements.

FIG. 32B illustrates an alternative embodiment in which working end 354includes irrigation port 355, suction port 356, and camera 358. Fluid357 can be flooded into the working area in front of tissue shredders359 to provide for visualization of the working area with camera 358.The fluid can be aspirated from the working area through suction port356.

FIG. 32C illustrates an alternative embodiment in which working end 360includes an axially slidable element 361 which includes a taperedoptical cone 363 at its distal end and a camera 362 proximal to thedistal end of cone 363. The optical cone can be advanced distally infront of shredders 364 to provide a space for visualization of theworking area with camera 362. The optical cone can be retracted withinworking end 360 when not in use.

FIGS. 33A-33C illustrate an alternative arrangement of the deliverysystem for visualizing the working area. FIG. 33A illustrates workingend 371 extending from delivery member 370 (an introducer is coupled tothe working end but is within delivery member 370). In thisconfiguration the shredders can remove tissue. The introducer andworking end are then retracted proximally as shown in FIG. 33B andremoved completely from the delivery member 370 (whose proximal end ispositioned external to the patient). A separate scope 372 is thenadvanced through delivery member 370 to the working area, as shown inFIG. 33C. The scope includes camera or image bundle 373, irrigation port374, suction port 375, and illumination bundle or LED 376. In use,tissue is removed with the shredders, then the working end is removed,the scope is then advanced to visualize the working area to determinethe progress of the procedure, and the scope is then removed. Thesesteps are repeated until the desired amount of tissue has been removed.

FIG. 34, steps A-E, illustrate an exemplary procedure for treating aherniated disc by removing nucleus tissue using a tissue removal deviceas described herein. As used herein, “disc tissue” can refer to thenucleus, annulus, and endplates. The following procedure can be used toremove nucleus tissue in the cervical, thoracic, or lumbar spine. FIG.34A shows disc 370 (vertebrae not shown for clarity) including annulus371 and nucleus 372. Using an imaging technique such as fluoroscopy or aCT scan, delivery member 373 (e.g., a delivery cannula) and dilator 374,which is shown with a “bullet” tip, are advanced towards disc 370 ineither a posterior or anterior approach. Dilator 374 and delivery member373 are then advanced through the annulus, as shown in FIG. 34B. Thedilator's bullet tip shape separates and expands the fibers of theannulus and does not cut or tear them. Once the distal end of deliverymember 373 is positioned at the desired location, dilator 374 iscompletely withdrawn from delivery member 373, as shown in FIG. 34C.Tissue removal device 375 is then advanced through delivery member 373,positioning the working end at the target tissue site, as shown in FIG.34D. The tissue removal elements are then activated by a physician via ahandpiece portion of the delivery system (not shown) to remove disctissue to repair a herniated disc, as shown in FIG. 34E. In thisembodiment delivery member 373 protects the annulus from the tissueshredders.

In an alternative method, rather than positioning delivery member 373under fluoroscopy or CT scan, dilator 374 incorporates an visualizationtool such as a camera which can be used to position delivery device 373.

An exemplary advantage of using a tissue removal device as describedherein to remove nucleus tissue is that the tissue can be removed withminimal damage to the annulus and endplates. The tissue processingelements can he manufactured to have dimensions that allows for safe andefficient removal of nucleus tissue. Additionally, by using small tissueprocessing elements, it is less likely that endplate or annulus tissuewill be damaged or unintentionally removed from the patient.

In other procedures the tissue removal device can specifically be usedto remove annulus tissue as well. For example, in complete disc removalprocedures, the tissue removal devices herein can be used to remove theentire disc.

The tissue removal devices herein can also be used to treat spinalstenosis. The tissue removal devices herein can be used to remove bloodclots in a thrombectomy, or to remove plaque in an atherectomy. Theseare merely examples of procedures that can be performed with the tissueremoval devices herein to remove tissue from a subject, and the devicesherein can be adapted to be used in other procedures. As necessary, theycan be adapted to be coupled to additional delivery system components tobetter adapt them for certain procedures.

In embodiments in which the blades are disposed at the distal end of theworking end, the working end can be advanced distally to engage andremove tissue. It may need to be retracted and advanced several times toremove the target tissue. It may also be necessary to change thedirection in which the working end is advanced each time to ensure thattissue is continuously and efficiently removed. In embodiments in whichthe blades are disposed on a side or sides of the working end, it may benecessary to laterally move the working end in a sweeping motion toremove the tissue. The working end may also be rotated during use (e.g.via rotation of the introducer).

In use, the tissue removal device may be used in combination withexpanders and/or distal protection devices. The tissue removal devicesherein may also be used in combination with forceps or claws to pull orpush tissue toward the blades.

The tissue removal devices as described herein may include a useractuation member, such as a hand-piece or other external controlmechanism for controlling and actuating the tissue removal device. Theactuation member generally includes an actuator adapted to turn theprocessing blades on and off, such as via a motor. The same actuator ora different actuator(s) can be adapted to control an irrigation/suctionsystem, such as by activating a pump to force a fluid distally throughan irrigation tube, while activating a vacuum to apply suction to pulltissue and irrigation fluid back proximally through the introducer. Anyother actuators can be incorporated into an external control mechanismto control the operation of the working end, drive mechanism,irrigation/suction system, etc.

According to some embodiments of the disclosure the drive mechanism mayhe powered by an electric motor located in proximity to the device, anelectric motor located at the end of a flexible shaft drive wherein themotor is remote from the device (e.g. outside the body when the deviceis used at the end a catheter or other delivery lumen in a minimallyinvasive procedure.

The tissue removal devices described herein are generally configured toremove target tissue from a subject. “Removing,” or the “removal” oftissue from a subject as used herein include any and all of the stepsinvolved in removing tissue at least from the target tissue area, and insome embodiments removing the tissue completely from the subject's body.The working end of the device comprises blades which initiate the tissueprocessing step. Processing tissue as used herein includes cuttingtissue, directing tissue from a location in the patient to a differentlocation, and capturing, or entraining tissue, as well as directingtissue proximally through the delivery system to a location external tothe patient. While “blades” as used herein may imply a cutting orshredding motion, the working end can includes many different types ofblades, not all of which cut, shred, or tear tissue; some may merely beinvolved in directing the tissue from one location to another (whetherfrom external to the device to a location internal to the device, orfrom a location internal to the device to a second location internal tothe device). In some cases in which a blade is described as merelydirecting tissue from one location to another, there may of course besome incidentally tearing, cutting, and/or shredding. Additionally, thetissue which is removed from the target tissue area may be stored atleast temporarily within the tissue removal device (e.g., in a tissuestorage chamber), or the tissue may immediately be directed from thetarget tissue area to a location external to the tissue removal device(e.g., through a suction lumen). In either case, the tissue can be movedwithin the tissue removal device by, for example without limitation, avacuum or other extraction mechanism such as an Archimedes screw orother mechanical conveyor.

The blades of the tissue removal devices may be configured to optimizeone or more of the above functions, and in some embodiments the bladesshape and function to be performed are influenced by the type of tissuethat is being removed.

FIG. 35 illustrates an exemplary embodiment wherein the axes of rotation384 of the rotors for blades 382 are substantially orthogonal to thelongitudinal axis 383 of at least the working end 381. As used herein,“substantially orthogonal” includes angles that are +/− about 30 degreesto the right angle. That is, angles between the two axes that are about60 degrees to about 120 degrees are considered substantially orthogonal.In some embodiments the rotors are not fixed relative to the workingend, but instead can be articulated in one or more directions. In theseembodiments the rotor axis is considered orthogonal if it can be rotated+/− about 30 degrees. In embodiments described above in which the bladesare oriented along a side of the working end, the axes of rotation ofthe blade rotors are also substantially orthogonal to the longitudinalaxis of at least the working end.

In generally, the tissue removal device includes at least one orthogonalrotor. FIG. 36 shows a distal end of a working end including a singlerotor 391 and stator 392 wherein the stator includes fingers or otherelements that work with the rotor to cause shredding or other disruptionof the tissue into small pieces that may be removed via the device fromthe body of the patient. In some embodiments the single rotor mayinclude a plurality of blade elements located in parallel with oneanother to allow wider contact with tissue to be removed.

FIG. 37 shows exemplary blade profiles, wherein profiles 400, 404, and408 would be most beneficial in removing soft tissue. Blade profiles412, 416, and 420 would be most beneficial in removing bone. Profile 400shows a blade shape for “hooking” which has a non-sharpened or dulledge. Profile 404 shows a blade for slicing, which is hooked-shaped witha sharp edge. Blade profile 408 can be used for shredding, and ishooked-shaped with serrations. The blade profiles for cutting bone aregenerally not hooked shaped and are more symmetrical. The shapes producea more robust blade for contacting hard materials. Blade profile 412 hasa sharp point and creates high pressure when cutting through corticalbone. Blade profiles 416 and 420 have a flat tip and square tip,respectively, and these blunt tips can be used for cortical bone but maybe more suited for cancellous bone.

FIG. 38 shows some additional exemplary blade types, supplementing someof the blade types shown in FIG. 37. Blades 422 a and 422 b illustrate abone grinder with a serrated tip. Blade 424A-434 d have a hooking shaftwhich can be used to remove soft tissue. The hooking shape can also havea sham edge as shown in 424 d. Blades 426A-436C can be used to tearthrough soft tissue, and can have a barbed edge as shown in FIG. 426C.Blade 428E-428B can be used for slicing soft tissue, and can have asharp edge as shown in 428B. Blade 430A-430C can be used for scoringsoft tissue, and can have a scoring edge as shown in 430 b.

FIGS. 39A-39C illustrate exemplary embodiments of double rotor bladedesigns. FIG. 39A shows a first rotor 440A and a second rotor 442 in anoverlapping, or interdigitated, configuration, with overlapping region444. Tissue 445 is being pulled centrally inward as the two rotorsrotate in opposite directions. This is the configuration of the bladesin the blade stacks shown in, for example, FIG. 7. FIG. 39B showsnon-overlapping, or non-interdigitated, rotors 446 and 448 pullingtissue 447 into the working end of the device. The left portion of FIG.39C provides a schematic illustration of a blade element of extendedheight (e.g. numerous layers) which may be used for transportingmaterial as opposed to tearing or shredding it. While the right mostside of FIG. 39C shows how the teeth of such blades may meshed but notcontacting so as to cause transportation of intervening material asrotation occurs. On the right of FIG. 39C, rotor 449 and rotor 450 havemeshed teeth (e.g., 451 and 452) like a gear which have tall profiles asshown. Rotors 449 and 450 can effectively work like a gear pump as apressure differential is created when the rotors begin to rotate, whichcan draw high viscosity gelatinous material (e.g., nucleus material froma spinal disc, blood clots, etc.) into the working end of the device.Unlike the blade stacks 102 and 104 as shown in FIG. 7, rotors 449 and450 can be fabricated from one solid extrusion, which gives the blades ataller profile.

FIGS. 40A (perspective view) and 40B (top view) illustrate analternative embodiment of working end 500 in which tissue is capturedand processed in multiple steps. The rotating elements at the mostdistal end (rotor 504) are not sharp and merely pull tissue into thehousing, while secondary blades (503 and 502) process the capturedtissue into smaller segments. Driving gear (left gear) and blade 502 isshown with a bore which is adapted to receive a driving pin (not shown)as described above. A drive mechanism (such as those described herein)can be activated to rotate the pin and thus drive gears 506, whichrotates rotors 502, 503, and 504 in the directions shown by the arrows.Working end 500 includes stator 501. Rotor 504 includes hooked-shapedgrasper teeth 517 and 518 which when rotating pull tissue (not shown)into the device in the direction of arrow 509, but do not necessarilyrip the tissue. Graspers 517 and 518 rotate and pull the tissue towardsfixed hooked-shape blade 508 which is fixed to the inside of side of thehousing. Blade 508 is formed in the housing to fit between graspers 517and 518 as graspers 517 and 518 rotate past blade 508. As shown in FIG.40B, the tissue is compressed between the rotor and the wall of thehousing and is sheared by fixed blade 508 and graspers 517 and 518. Asrotor 504 continues to rotate, graspers 517 and 518, in combination withsolid wall guide wall 510, pull the tissue into a first area between therotors where it is allowed to expand, as illustrated in FIG. 40B.Stripper 511 extends from the housing wall and is formed in between theplanes of grasper 517 and 518. Stripper 511 may extend between graspers517 and 518 to a location that provides near contact with a centralrotating shall of rotor 501 so as to inhibit passage of material fromthe interior of the working end to a position outside the working end.Stripper 511 preferably also has a configuration, e.g. slope or thelike, which helps remove material from graspers or blades 517 therebyhelping prevent the material from exiting the housing.

Grasper 520 on rotor 503 then grasps and pulls tissue towards the secondfixed blade 512, which is fixed to a second wall of the housing. Theprocess that occurred at the first fixed blade 508 is repeated again,and once again the tissue is then directed towards a third fixed blade515. Shredded material is directed proximally in the direction of arrow516, when it is extricated by a vacuum. In most the most preferredimplementation of the devices of the type exemplified in FIGS. 40A and40B, rotators that at located more proximally relative to the distal endof the working end preferably rotate at a faster rate than the next fordistal rotor and/or have more blade elements that can be used to extractmaterial from the grip of more distal blades and thus drive the materialdeeper into the working end and the sonic blade to further aid inreducing the size of the entrained material.

In variations of the embodiment of the FIGS. 40A and 40B, multiplerotors “n” may be located in parallel so that multiple rotors are usedto transport and breakdown material. The details of how this system ofrotors in series works is listed below.

The devices of the type of FIGS. 40A and 40B preferable include grippingblades shearing blades, externals stators internal stators of varyingthickness and spacing directing elements which are digitated or notalong with stripping element which are preferably digitated. The devicesalso include expansion areas which allow soft tissue to decompress orde-stretch while waiting for pick up or breakdown by a next series ofelements. In some embodiments, the fixed stators may be replace bymoving rotor elements. Internal stators may be used to shred incomingtissue at different levels of fineness. Progressive shredding maybeaccomplished by increasing the number of blade planes and stators foreach stage after the intake rotor or rotors. Progressive shredding andoutflow inhibition may also be accomplished by running the internalrotors at higher rates than that of the intake rotor and even that ofthe next more distal rotors. As illustrated in FIGS. 40A and 40B,directors 510, 511, 513, and 514 direct the material into the expansionareas where it will be ripped and pulled into the next set of rotors.Any excess material that is caught between the rotor blades of the firstshredder will be stripped and directed by be a stripper that isinterleaved with the blades rotor. The strippers 511 and 514 may act asa stators that void additional shearing. Directors 510, 511, 513 and 514are generally not interleaved with rotors but may be in someembodiments.

In the device of FIGS. 40A and 40B, tissue is pulled into the device byintake rotor, e.g. this may be defined as step 1. A second set ofstators 508 internal to the housing may provide tissue shredding. Asintake Rotor A continues around for the next exterior swath cut oftissue, potential tissue located in between the blades may be strippedaway by stripper 511 or by movement of blades 520. Tissue is directedinto an expansion region between rotors 504 and 503 and may be allowedto expand before being compacted and hooked by the next rotor 503.Tissue is cut or shredded from rotor 501A by the motion of rotor 503,which may be defined as step 2. As noted above rotor 503 may he rotatingat a higher rate than rotor 504. Next the tissue is directed into thegap between rotors 503 and 502 and may be allowed to expand before beingcompacted and hooked by the next rotor 502. Tissue is sliced again by ahigher density blade on rotor 502, which may be defined as shreddingstep 3. Rotor 502 may be rotating at a higher rate than rotor 503. Theprocess of progressive, i.e. stepped, shredding may be continue throughn number of stages until tissue has reached a desired size and then theindividual particles of tissue may be extricated through the device byvacuum and or via irrigation.

While FIGS. 40A and 40B show three rotary devices in series, in someembodiments there are more or less than three rotary devices. In someembodiments there is more than one rotor at each stage. For example,there can he two sets of three rotors in series, with the two setsadjacent one another in the housing. This can potentially increase therate of tissue processing as well as provide more efficient shearing oftissue.

While gear 502 in FIG. 40 is the driving rotor, any of the rotors can bethe driving rotor, such as rotor 503. In some embodiments the rates ofrotor rotation is not 1:1. In some embodiments the most distal rotor(i.e., rotor 504 in FIG. 40) rotates faster than the other rotors. Forexample, rotor 503 can rotate at 10 times the speed of rotor 504, whichcan increase the speed with which the tissue is processed in thehousing. In embodiments in which the rotors rotate at different speeds,the gears which rotate the rotors may not he in the same train or may bein the same train with different diameters and teeth counts,alternatively multiple drive trains can exist.

FIG. 41 illustrates an alternative design in which a plurality of bladerotors 530 and 532 direct tissue (not shown) towards vertical cutters534 which are fixed in place (e.g., fixed to a housing in a working endof the device). Vertical cutters have sharp edges 535. After passingthrough vertical cutters, the tissue can be rotary sliced or passedagain through a second set of vertical column cutters or rotatingcutters.

FIG. 42 shows an alternative embodiment of a ‘hybrid’ blade with teeththat are capable of both piercing, or cutting, into tissue to entrainit. The outer portions of the teeth 552 and 551 are intended to cut thetissue, while the inner portion 553 is intended to entrain the cuttissue and convey it into the instrument. In some embodiments, the outerportions are thinner (e.g., formed from a single relative thinmulti-material layer) and the inner portion is thicker (e.g., formedfrom one or more multi-material layers). In some alternative embodimentsthe blade may have a non-symmetric shape based on the intendeddirections of motion and use.

FIG. 43 illustrates an optional blade stagger design in which the tipsof teeth 106 are staggered a distance “S” from one another measuredcircumferentially or in an offset angular increment relative to adjacentblade tips. When more than two blades are used in a blade stack, thedistance S for a pair of blades can be the same or can be different thanthe distance S for a different pair of blades.

In some embodiments the distal end of the working end can include morethan two blade rotors sets. In some embodiments blade stacks may bestacked on one another. For example, two blade stacks can be stacked onthe top of two other blade stacks for form a four rotor blade system.Additionally, the axis of rotation of the blade stacks are notnecessarily parallel to one another. For example, a working end can have4 blade stacks pointing in the distal axial direction but rotated withrespect to each other for example to having rotation axes rotating aboutshaft positioned on the hour hand of a clock located at “12 o'clock,”3o'clock, 6 o'clock, and 9 o'clock positions. Wherein the axes ofrotation of the 12 o'clock and 6 o'clock rotors are parallel, and theaxes of the 3 o'clock and 9 o'clock rotors are parallel. One set of axesis perpendicular to the other set of axes. All four rotor sets may bedirecting the tissue centrally inward. In an alternative embodiment,there are three blade stacks and each is 120 degrees from each of theother blade stacks, and their axes of rotation form an equilateraltriangle at their points of intersection (e.g. 2 o'clock, 10 o'clock,and 6 o'clock).

In some embodiments blade tips, gear pins and other high wear surfacesmay be formed from a wear resistant material (e.g. rhodium or diamond)while other portions of the device may be formed from another materialthat is more suited to the functionality of the device as a whole (e.g.a more resilient or less brittle material, nickel cobalt, nickelphosphor, palladium).

In some embodiments, blades and/or blade stacks may rotate at differentrates or blades within a single stack may rotate at different rates.

In some embodiments the working end of the tissue removal device isformed with a length of about 4 mm, a width of about 2.5 mm and a heightof about 0.75 to 1.0 mm. In other embodiments the height may beincreased to several millimeters or decreased further, while the lengthand width may be increased many times (3-5 to even 10 times) or evendecreased. Stacks of shredders of different sizes (e.g. number ofshredding or intake rollers, or having diameters of such shredding orintake rollers) may be formed to provide a desired material interfaceconfiguration (e.g. cylindrical). Such configurations may have effectivecentral heights that approximate their widths. Such configurations mayhave, for example, rectangular configurations, stepped diamondconfigurations, stepped configurations approximate ellipses or circles(e.g. approximate the diameter of a delivery cannula.

In some embodiments portions of the working end are formed separatelyand then assembled. In some embodiment the working end is formed in afinal assembled state. In some embodiments the working end is coupled toother components of the delivery system (e.g., an introducer) afterassembly. In some embodiments components that move relative to oneanother are formed with fully or partially overlapping etching holes sothat improved flow paths are created for removing sacrificial material.

FIG. 44 illustrates an exemplary embodiment of components of a devicethat are formed in one configuration but separated from a finalconfiguration and are moved relatively toward one another after releasefrom sacrificial material. It may be desirable to form very small gapsbetween a rotating gear axial, shaft or boss relative to a surroundinghole, bushing or bearing. Due to minimum feature size limitation, directformation of moving components in desired configurations may bechallenging or not cost effective. FIG. 44 shows gear boss 650 andadjacent surfaces 652 and 654 in an “as-formed” spaced-apartconfiguration. Additionally, although not shown, the internal gearscould also be formed in a spaced-apart configuration from their adjacentmaterial. After fabrication, surfaces of material 652 and 654 are movedcloser to one another and locked in place by locking first lock element656 and second lock element 658. Gear boss 650 can then be disposed in afinal configuration closer to surfaces 652 and 654 than it would havebeen able exist in an “as-formed” configuration which was also the finalconfiguration.

FIG. 45 shows an exemplary embodiment in which a gear or boss isfabricated in an “as-formed” configuration in which it is out of planewith material which the gear or boss will ultimately be in-plane with ina final configuration after formation. Boss 660 is fabricated up and outof plane with 668, while gear 672 is fabricated out of plane with matinggear 670. Once fabricated, boss 660 is moved down into bore 662 so thatit is in-plane with surface 668, while gear 672 is moved down andin-plane with its mating gear 670. Appropriate clip or other retentionelements may exist to hold the components in their working positionsafter being moved there.

FIG. 46 illustrates an alternative embodiment similar to FIG. 44,wherein slide plate 684 includes protrusion 686 on one side adapted tofit within channel 668. Slide plate 684 is formed spaced apart from boss682, but after formation slide plate is slid into position, and the bossclearance is properly set. The slide plate can then be locked in place,such as by snap- locking or laser welding in place.

FIGS. 47A-47C illustrate an exemplary embodiment of a working end,including a gear train and two shredder rotors. FIG. 47A shows workingend 700 in an “as fowled” configuration with elements spaced apart tofit minimum feature size limitation. Working end includes first section704 and second section 702 spaced apart from one another, first boss710, first blade stack 706, second blade stack 708, second boss 712, andpin bore 714 in first section 704. FIG. 47B shows driving gear 716, gear718, and gear 719 in their as-formed configuration. The gears are formedspaced apart in order to create the proper gap dimensions between theteeth. FIG. 47C shows the design in a closed, final configuration inwhich section 704 and 702 are moved closer which reduces the gapsbetween surfaces of sections 704 and 702 and bosses 710 and 712. Thegear teeth are also moved closer to one another (not shown).

In some embodiments gap layers (i.e. intermediate tiers) may, forexample, be as little as about 2 microns or as much as about 10 microns,and more preferably be in the range of about 4 microns to about 6microns. Non-gap layers may, for example, be as large as about 20microns to about 50 microns or more, while in some embodiments thenon-gap layers may preferably in the range of about 20 microns to about30 microns.

FIGS. 48A-48C illustrate an embodiment of a tissue removal deviceincluding a core cutting saw 740 with a plurality of tissue removaldevices 742 therein. The device includes core cutting saw 740 with teeth741 formed in its distal end, wherein the saw 740 is adapted to rotatein the direction of the arrow shown. The core saw is cutting to theouter diameter of the device, where the tissue removal devices are notadapted to cut to that diameter. The tissue removal devices aredirecting material inside their housings and processing it for transportto the proximal end of the device. FIG. 48B depicts one of the removaldevices of FIG. 48A wherein element 748 rotates with it bladeinterdigitated with the blades on the stator as it forces material intothe remover. FIG. 48C shows the assembly of a rotating saw, a joinedrotating gear that engages drive gears on the removing devices which arefixed, or at least move at different rotational rates relative to thesaw and cylindrical gear FIGS. 48A and 48B. The working end (i.e. theremoving elements) may be fixed or non-rotating, rotating opposite tothe saw or simply rotating at a different speed relative to the saw.

In some embodiments the etching holes in the working end may be sealedafter release of sacrificial material.

In some embodiments of the working ends of the tissue removal devicesset forth herein, may include holes, textures, grooves, or otherfeatures which provide rotating elements, the shafts on which theyrotate, and/or to the surfaces surrounding the rotating elements withconfigurations that allow for aerodynamic or hydrodynamic bearingsurfaces that reduce friction during rotation of the elements.

In some embodiments, the tissue removal devices may be configured toremove soft tissue without damaging hard tissue, either by use ofselective blade configurations, operational speeds, and/or via clutchelement that halt rotation of removal elements if encountered tissuedoes not have the anticipated properties. Such clutch mechanism may bemechanical in nature or implemented via sensor input and associatedmotor control.

Some embodiments of the disclosure relate to devices and methods forremoving tissue from the human spine (e.g., the lumbar or cervicalspine). Such methods may be minimally invasive while others may not.Tissue removal devices such as the various shredder devices discussedabove may be used to remove tissue such as ligament, bone, cartilage,tendon, and disc (both nucleus and annulus), as well as fat, fascia, andmuscle in the area of the spine. Removal of such tissue may be a part ofmedical procedures for repairing a bulging or herniated discs, forrepairing spinal stenosis, or for other indications.

In some embodiments, a tissue removal device may be delivered to adesired surgical site via a rigid, flexible, steerable, or articulatedstructure, while optically visualizing the procedure using a rigid,flexible, steerable, or articulated endoscope that is separate from theremoval device. In some embodiments, a tissue removal device may bedelivered to a desired surgical site through a working channel, oralongside, a rigid, flexible, steerable, or articulated endoscope usedto visualize the procedure. In some embodiments, the tissue removaldevice may be introduced under fluoro guidance or guidance fee anotherimaging method.

In some embodiments, a tissue removal device may be delivered to adesired surgical site through a rigid, flexible, steerable, orarticulated structure and also incorporate one or more (e.g., two forstereoscopic visualization) imaging means such as a CCD or CMOS imagingchip, a fiber optic bundle, or single fiber endoscope (e.g., using thespectrally encoded endoscope technology developed by the Wellman Centerfor Photomedicine of Mass General Hospital), along with suitable opticssuch as lenses. The imaging devices may be located so that the opticalaxis substantially coincides with the centerline of the tissue removaldevice, or be offset from the centerline of the device. In someembodiments, the procedure may be visualized by the use of X-rays (e.g.,fluoroscopy or CT scanning), ultrasound, MRI, or other imagingmodalities, in addition to, or in lieu of, optical visualization viaendoscopes or other imaging means as described above.

In some embodiments, to enhance visualization, a transparent dome thatis hemispherical, wedge-shaped, or is otherwise appropriately shaped maybe provided to protect the optics and to provide a means fordisplacing/retracting/dissecting tissue as the device is pushed forward.Irrigation and/or mechanical action may be used in some embodiments tokeep the dome clean.

In some embodiments, the tissue removal device is activated (e.g.,shredder cutters rotated) only once it has been delivered to thesurgical site; prior to activation, it may be allowed to contact tissue(e.g., en route to the site). In some embodiments, the device may beprotected from tissue contact by retracting it inside a sheath, tube,catheter, or similar structure. In some embodiments, the tissue removaldevice may include fixed or moveable shields or shutters which move outof the way to allow device use, prevent damage to surroundingstructures, in some eases exposing only the tissue to be processed bythe device.

In some embodiments, it is desirable to simultaneously remove tissuefrom a wider area than is possible with the previously-disclosedShredder. In such embodiments, a shredder that is larger in width and/orheight may be used, and may involve more than two groups of rotatingcutters. In some embodiments, if the desired height exceeds that whichis practical to achieve using multi-layer multi-material electrochemicalfabrication methods as a single structure, two or more shredders may bestacked and operated as one.

Stacked shredders may be aligned, and joined by methods such as laserwelding, fasteners such as screws and rivets, swaging of featuresdesigned for joining, soldering, brazing, and adhesives. Such stackeddevices may be joined by connectors (e.g. male and female engagementelements formed with the devices themselves and engaged by stack mereact of aligned stacking. In other embodiments, engagement may occurafter stacking by deploying components formed with the devices on aselective basis. In some embodiments, disengagement of stacked devicesmay also be possible. In such stacked device embodiments, gear trainsmay be driven independently (e.g., at different speeds or the samespeeds, with correlated phase or un correlated phase) or jointly. Inembodiments in which the gear trains of joined shredders are drivenjointly, this may be accomplished when joining the shredders by aligningthe holes in the driven gears (which receive a drive shaft) and drivingall driven gears with an elongated shaft. Alternatively, the drivengears may be designed to be attached or keyed to one another so thatwhen one or more is driven by a drive shaft, all spin together.Shredders designed to be stacked may incorporate upper and/or lowerplates which are thinner (e.g., half the thickness or less) than if theshredder were designed for independent use, so that the combinedthickness of the upper plate of one shredder and the lower plate of theshredder above it is not excessive. If the stacked shredders areintended to form a cylindrical device (e.g., to remove tissue in acylindrical volume when plunged) or to occupy as much as possible of acylindrical lumen (e.g., sheath or working channel), then the shreddersmay be designed as shown in the example of FIG. 49 which provides aschematic view of the distal or working end of a plurality of stackedshredders where each shredder is sized to conform roughly to acylindrical overall shape. The working end is located within a sheath801 (e.g. a catheter or other lumen and may be extended from the sheathas appropriate. The working end, in this example, include doubleshredders 811-815 wherein a portion of the shredders may have differentconfigurations to provide an overall device or working end configurationof desired shape.

In some embodiments, in order to increase the hardness of the devicewhere in contact with tissue (especially for hard tissue such as bone),the contacting surfaces may be made from harder material, or have acoating of harder material. Such materials include electroplatedrhodium; vacuum-deposited nitrides, carbides, and oxides; and diamond,boron nitride, or other hard ceramic particles in a matrix of metal(e.g., co-deposited with electroless nickel) or resin.

In some implementations, jamming of the tissue removal device withtissue may be an issue. In some embodiments, reversing (e.g.,periodically or as-needed) the direction of the motion (e.g., theshredder cutters) may help to dislodge tissue causing jamming. In someembodiments, tissue caught within the shredder cutters or similarstructures, that might lead to jamming, could be dislodged/stripped fromthe cutters by suction, directed irrigation, or mechanical structuressuch as wiping or reciprocating elements.

While some tissue removal devices may not just cut tissue, but alsocapture and transport it away from the surgical site, in someembodiments suction capability (e.g., vacuum holes and manifoldinterfaced to a vacuum pump, peristaltic pump, etc.) may be incorporatedinto the device to facilitate removal of processed material. In someembodiments the tissue removal device may be interfaced to a devicehaving the ability to mechanically transport tissue (e.g., anArchimedes-type screw rotating within a sheath) larger distances (e.g.,to outside the body) than the device itself.

In some embodiments, the surgical approach to the tissue to be removedmay be substantially anterior or anterior oblique, while in someembodiments, it may be substantially posterior or posterior oblique.

In embodiments relating to spinal disc problems, closure of the annulusof the disc after removal of disk material (e.g., disc nucleus) may beperformed, for example, using suture material, or a tissue approximationdevice such as a clip, staple, or ratcheting fastener.

In variations of some of the above noted embodiments the effectivecutting, shredding or removal area of a device may be adjustable, forexample, by inclusion of an adjustable window on the removal deviceitself or on the catheter. Adjustability of a device may also allowdifferent teeth configurations (shape and or size) to take moreprominent positions depending on the type of tissue to be processed. Insome embodiments the same catheters that provide the tissue removaldevices may also provide suction or irrigation to be incorporated intothe same catheter).

In some embodiments, material extraction from a working site may occurby back and forth motion at different angles which are varied by varyingthe entry angle of a relative rigid insertion element. In otherembodiments, the tissue removal device may be located on flexible orguidable element that may be made to change shape by control wires orthe like which can cause the device to bend to the left of the rightwhile other movement may be obtained by rotating the device about itsaxis or by moving it back and forth. In some embodiments, the guidableelement may be moveable up, down, and left and right directions byappropriate manipulation. In still other embodiments, for example, asingle drive shaft operating all removal elements may be engaged by arotating element and the device may be pivotable to the left or right bynearly 180 degrees by the extension or retraction of control wiresengaged with the side of the device. Such devices would preferablyinclude flexible or pivotal lumen elements that would allow appropriateextraction of material (e.g. via vacuum) along with possible applicationof irrigation for blade cleaning or material extraction regardless ofthe pointing direction of the distal end of the shredder. Such apivotable device would allow access to forward, side facing, and backfacing regions for tissue removal.

The operation of removal devices in removal procedures as set forthherein may be done under the manual control of a physician or operatorwherein movement and extraction occur via a series of movements selectedby the operator. Alternatively, the extraction may occur via a computerdefined and controlled algorithm that directs the shredder through aseries of predefined motions and operations or via a series of motionsand operations that are dictated at least in part by sensor retrievedinput (e.g. visually, optically, conductively, capacitively,magnetically, or the like).

FIGS. 50A and 50B provide a schematic illustration of a shredding ortissue removal device, i.e. working end, 854 located within a lumen 853having an expanded distal end 852 and a smaller lumen 851 which may beused to feed additional tools or elements into or beyond the expandeddistal end of the lumen. The expanded distal end may be of fixed size ormay be controllable.

FIGS. 51A and 51B provide close (compacted) and open (expanded) views ofa sample device according to a procedural embodiment of the disclosure.The device includes an elongate delivery rod, tube or wire that may alsoprovide control functionality along with an expandable mesh or net likeelements that can be move from a contracted state 862C to an expandedstate 862E.

FIGS. 52A-52F illustrate the use of the devices of FIGS. 50A-50B and51A-51B in a thrombectomy application. FIG. 52A depicts the device ofFIGS. 50A and 50B inserted into a vessel containing a thrombus 871wherein the distal end 852 of the device is located in proximity to thethrombus. Next, in FIG. 52B, a guidewire or lumen 872 is extendedthrough and from lumen 254 though and beyond the distal end of thethrombus. In FIG. 52C the closed expander 862C is shown extending beyondthe distal end of the thrombus after which it is manipulated to attainopen state 862E. In FIG. 52E, the thrombus is shown being drawn in tothe catheter so that it may be macerated by the shredder 854. FIG. 52Fshows the state of the process after partial destruction and removal ofthe thrombus has occurred with a portion of it 871S being drawn down thelumen 851. Continued process will result in complete maceration of thethrombus or at least sufficient maceration to allow extraction of theremaining portion to safely occur (e.g. via entrapment in the distal end852 of lumen 851.

FIGS. 53A-53D show another exemplary embodiment of a tissue removaldevice. Device 5310 may employ any of the cutting heads describedherein, or other suitable cutting heads. In some embodiments, a doublerotor shredding head is employed at the distal end of device 5310 toselectively debride tissue down to the cellular level.

In this exemplary embodiment, handheld device 5310 includes a steppermotor 5312 at its proximal end. In other embodiments, other types ofelectric, pneumatic or hydraulic motors, servos, or other prime moversmay be used. The proximal end of motor 5312 may be provided with amanually turnable thumbwheel 5314, as shown. In this embodiment, thedistal output end of motor 5312 is provided with a housing 5316, whichis made up of a front cover 5318 and a rear cover 5320. Located distallyfrom housing 5316 are an outer shaft housing 5322, an outer shaft lockseal 5324, and a support clamp 5326. A non-rotating, outer support tube5328 extends from within the proximal end of device 5310 towards thedistal end of the device. Within support tube 5328, a rotating drivetube 5330 (best seen in FIGS. 53B and 53C) also extends from within theproximal end of device 5310 towards the distal end of the device. Thesupport tube 5328 and inner drive tube 5330 may collectively be referredto as an introducer. A cutter head assembly 5332, subsequently describedin detail, is attached to the distal end of support tube 5328.

As best seen in FIG. 53B, other components of device 5310 include motorshaft drive axle 5334, motor dog 5335, four bearings 5336, drive gear5338, driven gear 5340, inner drive shaft axel 5342, inner shaft lockseal 5344, vacuum gland disk 5346, vacuum seal lock housing 5348, vacuumseal lock 5350, vacuum hose barb 5352, irrigation fluid hose barb 5354,outer tube o-ring 5356, and two vacuum gland o-rings 5358. Various otherpins, dowels, fasteners, set screws, ball detents, shims and wave discsprings are shown in the figures without reference numerals. As will beappreciated by those skilled in this art, these non-referencedcomponents serve to align, retain and ensure the proper functioning ofthe other components of exemplary device 5310.

The two rotors of cutter head assembly 5332 located at the distal end ofdevice 5310 are driven by motor 5312 through drive tube 5330 and otherdrive components of device 5310, as will now be described in moredetail. As best seen in FIGS. 53B and 53C, a motor dog 5335 is attachedto the output shaft of motor 5312. Motor dog 5335 is coupled to motorshaft drive axle 5334, which is rotatably mounted in housing 5316 withtwo bearings 5336. Drive gear 5338 is rigidly fixed to motor shaft driveaxle 5334, and drives driven gear 5340 (as best seen in FIG. 53D.)Driven gear 5340 is rigidly fixed to inner drive shaft axel 5342, whichis rotably mounted in housing 5316 with two bearings 5336. Innerrotating drive tube 5330 passes through the center of inner drive shaftaxel 5342 and is rotatably fixed thereto. Drive tube 5330 extends fromthe proximal end of device 5310 to the distal end of the device throughthe non-rotating outer support tube 5328. The distal end of drive tube5330 (or a separate tube 5330′attached thereto) is provided with crownteeth around its periphery, as shown in FIGS. 54B and 56C, for meshingwith drive gear 5410. As drive tube 5330 is rotated about a longitudinalaxis of device 5310 by motor 5312 through the above-described drivetrain components, it drives drive gear 5410 about an axis that isperpendicular to the longitudinal axis, as can be appreciated by viewingFIG. 56C. Drive gear 5410 in turn drives other components of the cutterhead assembly, as can he appreciated by viewing FIG. 56E, and as issubsequently described in more detail.

In some embodiments motor 5312 is provided with feedback control forrotational velocity and torque. These two parameters can be used forcontrolling and monitoring changes in rotational velocity and the torqueload. For measuring rotational velocity, an encoder may be located atone or more of the cutter rotors, at the drive motor, or at anotherlocation along the drive train between the drive motor and cutterrotors. In some embodiments, the encoder is located at or close to therotors to avoid backlash associated with the drive train, thereby makingthe velocity monitoring more responsive and accurate. Encodertechnologies that may be used include optical, resistive, capacitiveand/or inductive measurement. To sense torque load, one or more straingages may be located at the cutter rotors, at the drive motor, or atanother location along the drive train between the drive motor andcutter rotors. Torque load may also be sensed by monitoring the currentbeing drawn by the motor. By sensing changes in velocity and/or torque,a controller associated with device 5310 can determine that the cutterrotors are passing from one tissue type to another and take appropriateaction. For example, the controller can sense when the cutter elementsare passing from soft to hard tissue, from hard to medium densitytissue, or from a cutting state to non-cutting state. In response tothese changes, the controller and/or device 5310 can provide audio,visual and/or tactile feedback to the surgeon. In some embodiments, thecontroller can change the velocity, direction or stop cutter rotors fromrotating in response to velocity and/or torque feedback. In oneembodiment of the invention, a typical cutting rotor speed is on theorder of 100 to 20,000 rotations per minute, and a typical torque loadis on the order of 0.25 to 150 mN-meter. Other sensors, such as apressure sensor or strain sensor located at the distal tip of device5310, may also be utilized to provide feedback that tissue cuttingelements are moving from one tissue type to another. In someembodiments, an impendence sensor may be located at the distal tip ofthe device, to sense different tissue types or conditions, and providecorresponding feedback for tissue cutting control when the tissue beingcut by the cutter head changes. Such a pressure sensor feedback controlarrangement can be used with types of cutting devices other than thosedisclosed herein.

Referring now to FIG. 53C, irrigation fluid hose barb 5354 is providedon the lower side of outer shall housing 5322 of exemplary device 5310.Hose barb 5354, or a similar fluid line coupling, may be connected to asupply of irrigation fluid. The lumen of hose barb 5354 is in fluidcommunication with an internal irrigation fluid cavity 5360. Fluidcavity 5360 surrounds internal drive tube 5330, and is bounded on itsproximal end by o-ring seal 5358 around drive tube 5330. Fluid cavity5360 is hounded on its distal end by o-ring seal 5356 around outersupport tube 5328. This arrangement allows drive tube 5330 to rotate,but constrains irrigation fluid delivered from hose barb 5354 to travelonly through the annular space defined by the outer surface of drivetube 5330 and the inner surface of support tube 5328. Irrigation fluidmay thus flow distally through the annular space to the distal end ofdevice 5310.

As shown in FIGS. 54B and 56A, one or more drive aligner rings 5412 maybe provided between outer support tube 5328 and inner drive tube 5330along their lengths to support drive tube 5330 as it rotates. In orderto allow the flow of irrigation fluid between the tubes 5328 and 5330,rings 5412 may be provided with one or more channels 5414 as shown. Whenthe distal flow of irrigation fluid reaches the cutter head assembly5332, it continues to flow distally into lug 5416. To enable the fluidflow, lug 5416 is provided with fluid channels 5418 located along theouter walls of its central bore, as best seen in FIGS. 54C, 55C. As canbe appreciated by viewing FIG. 56C, irrigation fluid passes distallybetween inner drive tube 5330 and lug 5416 through channels 5418 (onlyone channel shown in FIG. 56C). As shown in FIG. 56B, irrigation fluidflowing distally through channels 5418 is directed toward the outsideportions of cutting elements. In this embodiment, the outside portionsof cutting elements are rotating distally, away from the fluid flow,while the inside portions of cutting elements are rotating proximally,toward the center of lug 5416 and drive tube 5330.

In some embodiments, the irrigation fluid serves multiple functions. Theirrigation fluid can serve to lubricate the cutting elements, drivegears, journal bearings and other components as the parts rotate. Theirrigation fluid can also serve to cool the cutting elements and/or thetissue being cut, absorbing heat and carrying it away as the irrigationfluid is removed from the patient. The fluid can serve to flush tissueparticles from the moving parts to prevent them from becoming clogged.The fluid can also serve to carry away the tissue portions being cut andremove them from the target tissue site. In some embodiments, theirrigation fluid is discharged from the cutting device and may beremoved from the target tissue site with other, traditional aspirationmeans. With the current exemplary cutting device 5310, however, theirrigation fluid and/or other bodily fluids may be removed from thetarget tissue site by the cutting device 5310, as will now be describedin detail.

As previously described, irrigation fluid may be delivered to cuttingelements and/or a target tissue site through device 5310. Exemplarydevice 5310 is also constructed to remove the irrigation fluid andtissue portions cut from the target tissue site through the shaft ofdevice 5310. As can be appreciated by viewing FIGS. 56B and 56F, the twointerleaving stacks of cutting elements, also referred to as rotors 5610and 5612, have an overlapping section 5614 in the center of cutter headassembly 5332. The two rotors 5610 and 5612 may be rotated in oppositedirections (as depicted by arrows A and B in FIG. 56F) such that eachrotor engages target tissue and pulls it towards the central overlappingsection 5614. In overlapping section 5614, the tissue is shredded intosmall pieces by the interdigitated cutting elements, as is subsequentlydescribed in more detail. The small tissue portions are generallypropelled in a proximal direction by rotors 5610 and 5612, away from thetarget tissue site and into the cutter head assembly 5332. As can beappreciated by viewing FIG. 56B, the shredded tissue portions emergefrom rotors 5610 and 5612 substantially along the central axis of lug5416 (and therefore also the central axis of drive tube 5330. Withsufficient irrigation fluid being supplied to the tissue cutting area,and sufficient aspiration being provided from the proximal end of thedevice, irrigation fluid around rotors 5610 and 5612 carries the cuttissue particles proximally down the center of drive tube 5330. As shownin FIG. 53C, the proximal end of drive tube 5330 is in fluidcommunication with hose barb 5352 located at the proximal end of device5310. A traditional aspiration device or other suction source may beattached to device 5310 through hose barb 5352 or other suitable fluidcoupling to collect the spent irrigation fluid and cut tissue portions.

In some embodiments, the cut tissues portions emerging from hose barb5352 may be collected for testing. The tissue portions may be separatedfrom the irrigation fluid, such as by centrifugal force, settling and/orfiltering. The tissue portions may be measured to precisely determinethe mass and/or volume of tissue removed. The pathology of some or allof the tissue portions may also be determined. In some embodiments, theabove testing may be performed during a surgical procedure so thatresults of the testing may be used to affect additional stages of theprocedure.

According to aspects of the invention, the inside diameter of drive tube5330 may be much larger than the maximum dimension of the tissueportions traveling through it. In some embodiments, the maximum tissuedimension is less than about 2 mm across. In one exemplary embodiment,the inside diameter of drive tube 5330 is about 3 mm, the outsidediameter of the support tube 5328 is about 5.6 mm, and the maximumdimension of the tissue portions is about 150 microns. In anotherexemplary embodiment, the inside diameter of drive tube 5330 is about1.5 mm, the outside diameter of the support tube 5328 is about 2.8 mm,and the maximum dimension of the tissue portions is about 75 microns. Inother embodiments, the inside diameter of drive tube 5330 is betweenabout atm and about 6 mm. In some embodiments, the maximum dimension ofthe tissue portions is at least one order of magnitude less than adiameter of the tissue removal lumen. In other embodiments, the maximumdimension of the tissue portions is at least twenty times less than adiameter of the tissue removal lumen. In some embodiments, the maximumdimension of the tissue portions is less than about 100 microns. Inother embodiments, the maximum dimension of the tissue portions is about2 microns.

Referring now to FIGS. 54A-54C, an exemplary cutter head assembly 5332is described in more detail. Cutter head assembly 5332 may be used withdebriding device 5310, shown in FIGS. 53A-53D. As best seen in FIG. 54B,cutter head assembly 5332 includes lug 5416, drive gear 5410, rotorhousing assembly 5420, aligner pin 5422, and aligner cap 5424. Lug 5416is provided with a cutout on its distal end for receiving rotor housingassembly 5420. Beneath the rotor housing cutout, lug 5416 has a circularrecess for receiving drive gear 5410. A bore is provided in the bottomof lug 5416 for receiving the head of aligner pin 5422. When cutter head5332 is assembled, the shank of aligner pin 5422 passes through the boreof lug 5416, through a square aperture in the center of drive gear 5410,through a bore in the proximal end of rotor housing assembly 5420, andinto a large diameter bore through the top of lug 5416. Aligner cap 5424is received with the large diameter bore in the top of lug 5416, and isfastened to aligner pin 5422 by a press fit, weld, threads, a separatefastener, or other suitable means. In this assembled arrangement, bestseen in. FIG. 56H, pin 5422 and cap 5424 retain rotor housing 5426 frommoving longitudinally relative to the central axis of the instrument,and rotor housing 5426 and drive gear 5410 retain pin 5422 and cap 5424from moving radially relative to the central axis of the instrument. Pin5422 and cap 5424 spin together as a unit relative to lug 5416, andserve to align drive gear with the distal end of drive tube 5330′, aspreviously described. Pin 5422 also serves to transmit torque from drivegear 5410 to gear 5616, which resides inside the rotor housing directlyabove drive gear 5410, as shown in FIG. 56H.

FIGS. 55A-55D show further details of lug bearing 5416, which forms thebase of cutter head assembly 5332, shown in FIGS. 54A-54C. Assubsequently described in further detail, various different cutter headsmay alternately be inserted into and securing within the slot shapedopening in the distal end of the lug bearing.

FIGS. 56A-56H show the overall construction and operation of the variouscomponents of the rotor housing assembly 5420, and their interactionwith the other components of the cutter head assembly 5332, shown inFIGS. 54A-54C. The device of this embodiment utilizes two front cuttingrotors. The two rotors are driven inward toward one another at similarspeeds. The rotors are situated approximately perpendicular to theinline axis. This device may be referred to as a shredder.

FIG. 56A is a distally looking axial view showing the relationship ofouter support tube 5328, drive aligner ring 5412 and inner drive tube5330. FIG. 56B is a distally looking axial view showing the relationshipbetween rotor housing 5426, lug 5416, and other components of the cutterhead assembly 5420. FIGS. 56C-56G are a series of oblique,cross-sectional views taken at various elevations through the cutterhead assembly 5332, showing the various layers of components progressingfrom the bottom to the top of the assembly. Starting with FIG. 56C, lug5416 and drive tube 5330′ are shown in cross section with the rotorhousing assembly 5420 removed to expose drive gear 5410. As previouslydescribed, drive gear 5410 resides in a circular cutout within lug 5416and is driven by crown teeth located on the distal end of drive tube5330, or a component 5330′ connected to the distal end of drive tube5330. Drive gear 5410 mates with a square shank portion of aligner pin5422, which passes through a square aperture in the center of drive gear5410, thereby rotatably driving pin 5422. FIG. 56D shows a bottom plateportion of rotor housing 5426 residing in its cutout within lug 5416 andcovering most of drive gear 5410. A pair of apertures is providedthrough the bottom plate portion of rotor housing 5426 to rotatablyreceive axels 5618, 5618 from rotor assemblies 5610 and 5612. FIG. 56Eshows gears 5616, 5620 and 5622 rotatably mounted on the bottom plateportion of rotor housing 5426. Gear 5616 has a square, central aperturefor receiving the square shank portion of aligner pin 5422. As can beseen, gear 5622 meshes with gear 5620, which, in turn meshes with gear5422. With this arrangement, drive tube 5330 or end component 5330′drives drive gear 5410, which drives aligner pin 5422, which drives gear5616, which drives gear 5620, which drives gear 5622. Gears 5620 and5622 each drive an axel 5618, which in turn drive rotors 5610 and 5612,respectively, in opposite directions as shown in FIG. 56F by arrows Aand B. As can be seen in FIG. 56E, gear 5622 has a smaller pitchdiameter than that of gear 5620 in this embodiment, which causes rotor5612 to spin at a faster rotational velocity than that of rotor 5610. Inother embodiments, the rotors may be driven at the same rotationalvelocity. As can be appreciated by viewing FIGS. 56E and 56F, a middleplate portion of rotor housing 5426 separates gears 5616, 5620 and 5622(below the plate) from rotors 5610 and 5612 (above the plate). FIG. 56Fshows rotor housing fins 5624 and 5626 interleaved between each of theblades of rotors 5610 and 5612, respectively. Fins 5624 and 5626 serveto guide cut tissue portions toward the center of drive tube 5330,rather than allow them to exit through the sides of the rotor housingand back into the patient. FIG. 56G shows the top plate portion of rotorhousing 5426 covering most of rotors 5610 and 5612, with rotor axels5618, 5618 and aligner pin 5422 protruding through. It can be seen bycomparing FIGS. 56F and 56G that the blades of rotors 5610 and 5612protrude further in the distal direction from the top plate portion ofrotor housing 5426 than they do from the middle plate portion. In otherembodiments, the protrusion distances can be equal, or reversed fromthose shown in FIG. 56G. In some embodiments, the blades may protrudefrom the housing by up to 500 microns. In other embodiments, the bladescan be recessed from one or both portions of the rotor housing, assubsequently discussed in more detail.

FIG. 56H shows a cross-sectional view taken along a vertical centerlineof the cutter head assembly 5332.

FIGS. 57A-57J show further details of an exemplary rotor housingassembly 5420′. Assembly 5420′ is constructed and operates in a mannersimilar to assembly 5420 as previously described in reference to FIGS.54A-54C and 56A-56H, but has a different blade configuration. As shownin FIG. 57A, rotor housing assembly 5420′ includes a pair of rotors5610′ and 5612′, each rotatably mounted in rotor housing 5426 by an axel5618. In this embodiment, rotors 5610′ and 5612′ are configured torotate in opposite directions to draw tissue into a center, overlappingregion where the tissue is shredded.

Referring to FIGS. 57B and 57C, the components of rotor housing assembly5420′ are shown. Assembly 5420′ includes housing 5426, a pair of axels5418, and gears 5410, 5620 and 5622, as previously described. Rotor5610′ includes two blades 5710 interspersed with three spacer rings 5714on first axel 5418. Rotor 5612′ includes three blades 5712 interspersedwith two spacer rings 5716 on second axel 5418.

It should be noted that while rotor housing assembly 5420′ is shown inan exploded format for clarity in FIGS. 57B and 57C, suggesting that thecomponents are fabricated separately and then assembled usingtraditional assembly processes, this may or may not be the case,depending on the embodiment. In some embodiments, rotor assembly 5420′is assembled this way. In other embodiments, assembly 5420′ may be builtin layers, such as by using the MEMS fabrication processes describedearlier in this disclosure. For example, after portions of housing 5426and gears 5410, 5620 and 5622 are built up in layers, bottom blade 5712,bottom spacer 5714, and housing fin 5624 are formed together in one ormore layers. Following this layer, bottom blade 5710, bottom spacer5716, and bottom housing fin 5626 may be formed together in one or morelayers. The process may be repeated until the entire rotors 5610′ and5612′ and surrounding components are formed. A thin sacrificial layermay be formed between adjacent layers of components to separate thecomponents from one layer from components of adjacent layers.Sacrificial material may also be formed in portions of eachnon-sacrificial layer to separate components on that layer, createdesired voids in the finished assembly, and to provide a substrate forforming components in subsequent layers above. With such a fabricationtechnique, rotor 5610′ may be formed as a single unitary structureinterleaved with portions of rotor housing 5426, rather than separatecomponents (i.e. axel 5418, spacers 5714, blades 5710, and gear 5620.)Similarly, rotor 5612′ may be formed as a single unitary structureinterleaved with portions of rotor housing 5426, rather than separatecomponents (i.e. axel 5418, blades 5712, spacers 5716, and gear 5622.)In some embodiments, combinations of fabrication and assembly techniquesmay be used to create the rotor housing and/or cutter head assemblies.

Referring to the top view shown in FIG. 57D and the bottom view shown inFIG. 57E, it can be seen that in this embodiment the axel 5418 of rotor5612′ is more distally located than axel 5418 of rotor 5610′. It canalso be seen that while a top plate portion of rotor housing 5426 coversmost of rotor blades 5710 and 5712, the blades protrude less from amiddle and bottom plate portion of housing 5426. Further details ofprotruding blades and rotor characteristics are subsequently discussedin reference to FIG. 57J.

Referring to the side view shown in FIG. 57F, it can be seen that thethree blades 5712 of rotor 5612′ are interleaved in a proximal region byrotor housing fins 5626, in a central region by spacers 5716, and in anopposite side region (seen only in a distal region of the blades in FIG.57F) by blades 5710 of opposing rotor 5610′.

A front or distal end view is shown in FIG. 57G and a rear or proximalend view is shown in FIG. 57H. As depicted in FIG. 57G, very small gapsor interference fits 5717 between overlapping blades 5710 and 5712 aredesirable in some embodiments. Similarly, very small gaps orinterference fits 5719 between blades 5712 and adjacent portions ofrotor housing 5426 are desirable in some embodiments, as will besubsequently described in more detail.

FIG. 57I shows a cross-sectional plan view of the gear train located inthe lower portion of rotor housing 5426 of assembly 5420′.

Referring to the cross-sectional plan view of FIG. 57J, the bottom twoblades 5712, of rotor 5612′ and the bottom blade 5710 of rotor 5610′ areshown. As shown, blades 5710 have a larger outer diameter than that ofblades 5712. But because axel 5418 of rotor 5612′ is located moredistally than axel 5418 of rotor 5610′, blades 5712 protrude moredistally from the bottom of rotor housing 5426 than do blades 5710 ofrotor 5610′. It can also be seen that teeth 5718 and associated troughs5720 of blades 5712 are configured to be rotationally out of phase withthose of other blades 5712 of rotor 5612′. As will subsequently bediscussed in more detail, this arrangement can tune rotors 5612 toselective cut certain types of tissue and avoid cutting other types oftissue.

Various rotor gaps can be seen in FIG. 57J. For example, gap 5722 isshown between the tips of blade teeth 5718 of rotor 5612′ and spacerring 5714/axel 5418 of opposing rotor 5610′. Gap 5724 is also shown,between the tips of blade teeth 5718 of rotor 5612′ and the adjacentportion of housing 5426. Gap 5726 is also shown, between spacer ring5714/axel 5418 of rotor 5610′ and the adjacent portion of housing 5426.In some embodiments, it is desirable to keep gaps 5722, 5724 and 5726very small, to ensure that tissue portions/particles that pass throughrotors 5610′ and 5612′ are first cut to a very small size, and to avoidjamming or clogging rotors 5610′ and 5612′. In some embodiments, thesegaps are fabricated as small interferences between the adjacent parts sothat when the rotors are first rotated, the adjacent parts hit eachother and wear down or burnish each other. In this manner, after a breakin period, smaller interference or zero clearance fits are createdbetween the adjacent moving parts. Gap distances that applicants believeare advantageous include less than about 20 microns, less than about 10microns, less than about 5 microns, less than about 1 micron,substantially zero, an initial interference fit of at least 2 microns,and an initial interference fit of about 5 microns.

In operation, the clatter elements of rotor housing assembly shown inFIGS. 57A-57J serve to grab tissue from a target source, draw the tissuetowards a central region between the blades, cut the tissue from thesource, and morcellate the tissue in small pieces for transport awayfrom the body. In other embodiments, separate cutter elements may beused for these various functions. For example, one blade or blades maybe used to cut tissue from the source, while another blade or set ofblades may be used to morcellate the cut tissue.

Components of cutter head assembly 5332, including rotor housingassemblies 5420 and 5420′, may be fabricated using processes such aslaser cutting/machining, photo chemical machining (PCM), Swiss screw,electro -discharge machining (EDM), electroforming and/or otherprocesses for fabricating small parts. Wafer manufacturing processes maybe used to produce high precision micro parts, such as EFAB, X-ray LICA(Lithography, Electroplating, and Molding), and/or UV LIGA.

FIGS. 58-65 depict various other aspects of cutting blades useful forselective tissue removal, according to aspects of the invention.

In some embodiments, the key to the shredder's ability to selectivelyremove tissue is attributed to the protrusion of the rotating cuttersfrom the housing and the design of a tooth pitch (space between the tipsof adjacent teeth) of each rotor. In some embodiments, the protrusionsets the depth of the inward cut for the tips of the rotor. This inwarddepth controls the thickness of tissue being removed. The tooth pitch ornumber of teeth circumferentially about the rotor diameter provides anopening for individual tissue fibers and/or fiber bundles to be hooked,tensioned and drawn between the cutters.

From the point of view of the selected tissue, the tooth pitch andprotrusion may be designed to grasp the smallest fibers or fiber bundlesthat are to be removed. From the point of view of the non-selectedtissue, the tooth pitch may be many times smaller than the fiber orfiber bundle, and the protrusion may also be equally smaller than thefiber/bundle diameter.

As previously described, FIGS. 57D and 57E show the exemplary protrusionof blades 5710 and 5712 as viewed from the top and bottom of a rotorhousing assembly 5420′, respectively. As shown in FIG. 57D versus 57E,the protrusion is more exposed on the top side than the bottom in thisembodiment. In other embodiments, the cutter device has the sameprotrusion for both sides. Biasing the protrusion more on one side thanthe other can provide advantages such as cutting/shreddingdirectionality and/or additional safety. Blade protrusion distances thatapplicants believe are advantageous include less than about 100 microns,less than about 10 microns, substantially flush with the housing,recessed a minimum of about 5 microns, and recessed a minimum of about10 microns.

For tooth pitch, FIG. 58 shows a rotor 5810 with two blade disks 5812and 5814. The pitch P is the distance from one tooth tip 5816 to thenext tooth tip 5816 along an imaginary circle circumscribing the outercircumference of the blade. The trough diameter or depth D generally isthe distance between the tooth tip 5816 and the low point between thetooth tips. In many embodiments, the trough is a critical geometrycomponent that enables tissue selectivity. Additionally, the troughopening O (i.e. the distance from tooth tip 5816 to the tooth back 5818of an adjoining tooth) can determine the size of the “window” forcapturing a fiber or fiber bundle diameter.

As shown in FIG. 58, teeth from one blade 5812 can be designed to be outof phase with teeth from another blade 5814. Designing the blades to beout of phase from one another can be used to reduce the effective troughdiameter by having the teeth of one disk overlap the troughs of anotherdisk. This makes the device more suitable for removing tissue in thinplanes (shaver). A device designed to use this planing mode may rely ona depth stop from the rotor housing to control the thickness of tissueremoved.

Although the mechanical aspects are important attributes of tissueselectivity at this scale, there is another important feature thatenables or further enables selectivity in some embodiments. Aspreviously described, the electronic control system for a closed loopmotor drive can be designed and programmed to enable the sensing of thetorque load (changes in electrical current) and/or changes in velocityat the blade rotors as they are being loaded by the tissue. In someembodiments, this is very important when going from one tissue planeinto another, i.e. muscle to cartilage, cartilage to bone, fiavum todura, tumor to nerve, etc. For the cutting of each tissue plane therecan be a known mechanical load that is imparted to the cutter head andsensed by the motor drive electronics and/or microprocessor. When aknown load signature changes (with the exception of a no loadcondition), the system can recognize this change. The surgeon can bealerted to this change, the motor can be stopped under control or themotor speed can be changed to an optimal level for the next tissue typeto be cut.

For a closed loop motor controller, the output current can be limitedand monitored continuously with a high speed microprocessor (torquesensing). Likewise, for velocity monitoring, the servo gains can be setso the motor is under-damped. The change in velocity may be indicated bya tachometer and can be used to indicate a change in load at the cutterhead. Either of these methods of monitoring a change in load (torquesensing, such as by monitoring current) or a change in velocity(velocity sensing, such as with a tachometer) alone or in combinationenable a highly sensitive method of measuring tissue load and detectingtransitions in tissue structures.

In some embodiments, tooth protrusion, tooth pitch, troughdiameter/depth, and trough opening are key geometric blade features thatenable selective tissue removal. The descriptions below that accompanyFIGS. 59-65 illustrate these concepts.

FIG. 59 shows the details of blade protrusion from the edge of ahousing.

FIG. 60 shows how a housing is being used as a depth stop forcontrolling the thickness of tissue being removed from the source. Insome embodiments, the protrusion depth is as small as an individual cellor fiber diameter of 2 microns.

FIG. 61 shows the diameter of the tooth trough matching the diameter ofthe fiber or cell. In some embodiments, the tooth trough diameter is assmall as an individual cell or fiber diameter of 2 microns.

FIG. 62 shows the details of selectivity from small fibers (selected) tolarge fibers (non-selected).

FIGS. 63A-63E show the details of how a tooth tip's angle of attack canbe adjusted to further enhance the selective cutting attributes. Bycreating a negative angle of attack as shown in FIGS. 63C-63E, the toothtip is generally only effective when the fiber diameter is less than orequal to the trough diameter. When the fiber diameter is greater thanthe trough diameter, the fiber is pushed away from the tooth, asdepicted in FIG. 63E. The negative angle of attack can ensure therepulsion of the larger fiber from the tooth's grasp. A positive angleof attack (FIG. 63A) or a neutral angle of attack (FIG. 63B), on theother hand, is less selective than the negative angle of attack (FIG.63C). Adjusting the tip pitch, trough depth, trough opening, protrusiondistance, tooth speed, etc., of tooth tips having positive or neutralangles of attack can enable these tips to also be selective of the typeof tissue they will and will not cut.

FIG. 64 shows different tooth geometries that can be designed into eachrotor. In FIG. 64A, a basic unidirectional grasping tooth is shown. InFIG. 64B, a dual purpose unidirectional tooth 6412 is shown. This designhas a leading grasper type tooth 6414 followed by teeth 6413 that can beused for removing harder materials such as ligament and bone. FIG. 64Cshows a bidirectional tooth 6418 with a grasping cutter 6414 at each endof the tooth. This dual direction cutter can cut in clockwise andcounter-clockwise directions by grasping, pulling and cutting tissuefrom the source, working in the same manner as tooth 6410 depicted inFIG. 64A. FIG. 64D shows a bidirectional cutter 6420 with the samebidirectional cutting attributes as tooth 6418 in FIG. 64C, but withsmaller tooth features 6416 between the two large leading edges, for usein removing harder materials such as ligament and bone.

In FIG. 65, two rotary blades are shown with fibers in tension. In somedouble blade cutter embodiments, the ability to pretension the fiberstightly before cutting is a key attribute. Tensioning fibers beforepulling them between the rotors and shearing them from the sourceenables the device to remove soft tissue in a swath that is as wide asor wider than the width or diameter of the cutter head. This process ofpre-tensioning the tissue fibers before cutting enables soft tissue tobe cut and/or removed in a manner similar to how rigid materials areprecisely cut and shaped using controlled industrial machiningprocesses.

Tooth tip velocity along with tooth geometry is another means ofcontrolling selective tissue removal, according to aspects of thepresent invention. A cutting device can be made non-selective for aparticular tissue by adding a negative angle of attack to the teeth anddriving the rotors at a fast speed, such that the tissue fibers arebumped or pushed away from the tooth troughs. By decreasing the speedalong with the use of suction and/or pressure against the target tissue,the selected fibers matching the trough diameter are pulled inwardbetween the blade rotors. At this point, the device works at an optimalspeed for selective tissue removal without abrasion or tearing to thelarger non-selected tissue fibers.

In some embodiments, the target tissue being cut is hydrated andgenerally has a nominal fiber diameter of about 6 to about 9 microns. Insome embodiments, the target tissue being cut is dry and generally has anominal fiber diameter of about 5 to about 6 microns. In someembodiments, the tissue fibers are connected together in bundles havinga nominal diameter of about 250 microns.

Typical dimensions in some embodiments include:

-   Housing diameter: 6 mm or less-   Blade diameter range: 0.75 mm to 4 mm-   Tip to Tip range: 0.2 mm to 1 mm-   Trough diameter range: 2 microns to 0.5 mm-   Blade protrusion range: 2 microns to 2 mm    The tip to tip distance is typically at least two times the trough    diameter for hook type teeth.

FIGS. 66A-66M show 13 further examples of cutter heads constructedaccording to aspects of the present invention.

The tissue cutting devices disclosed herein may be configured for use ina variety of procedures. An example of a cardiac application is usingthe inventive devices to selectively remove endocardium, with thecutting device configured to leave the underlying myocardium uncut. Anexample of a tissue removing application involving the esophagusincludes selectively removing mucosa, leaving the submucosa. Such atherapy would be useful for treating Barrett's disease. Examples in thespinal area include selectively removing flavum, with the cutting deviceconfigured to stop removing tissue when dura is reached, leaving thedura intact. Selective removal of flavum but not nerve root is anotherembodiment. A cutting device constructed according to aspects of theinvention can also be configured to remove flavum without cutting bone.In this embodiment, the rotor velocity could be changed and/or thecutting elements could be changed after the flavum is removed such thatsome bone tissue could then be removed. Examples in the neurovasculararea include selectively removing cancerous tissue while not cuttingadjacent blood vessel tissue or nerve tissue. In the rheumatology field,tears in labral target tissue may be selectively removed whilepreserving adjacent non-target tissue, such as in the hips, shoulders,knees, ankles, and small joints. In some embodiments, small teeth on therotors can interact with micron scale fibers of cartilage, removingtissue in a precise way, much like precision machining of materials thatare harder than tissue. Other target tissues that may be selectivelyremoved by the inventive devices and methods described herein includecartilage, which tends to be of a medium density, periosteum, stones,calcium deposits, calcified tissue, cancellous bone, cortical bone,plaque, thrombi, blood clots, and emboli.

It can be appreciated by those skilled in the art of tissue removal thatsoft tissue is much more difficult to remove in a small quantitiesand/or in a precise way than harder tissue such as bone that may begrinded or sculpted, since soft tissue tends to move or compress whenbeing cut, rather than cut cleanly. Cutting tissue rather than removingit with a laser or other high energy device has the advantage of notoverheating the tissue. This allows the tissue to be collected and itspathology tested, as previously described.

In some embodiments of the invention, the selective tissue cutting toolmay be moved laterally along a tissue plane, removing thin swaths oftissue with each pass until the desired amount or type of tissue isremoved. In some embodiments, the tool may be plunged into the targettissue in a distal direction, until a desired depth or type of tissue isreached. In any of these embodiments, the tool may cut a swath or borethat is as large as or larger than the width of the tool head. In someembodiments, the cutting elements are distally facing, laterally facing,or both.

Further Comments and Conclusions

Structural or sacrificial dielectric materials may be incorporated intoembodiments of the present disclosure in a variety of different ways.Such materials may form a third material or higher deposited on selectedlayers or may form one of the first two materials deposited on somelayers. Additional teachings concerning the formation of structures ondielectric substrates and/or the formation of structures thatincorporate dielectric materials into the formation process andpossibility into the final structures as formed are set forth in anumber of patent applications filed Dec. 31, 2003. The first of thesefilings is U.S. Patent Application No. 60/534,184 which is entitled“Electrochemical Fabrication Methods Incorporating Dielectric Materialsand/or Using Dielectric Substrates”. The second of these filings is U.S.Patent Application No. 60/533,932, which is entitled “ElectrochemicalFabrication Methods Using Dielectric Substrates”. The third of thesefilings is U.S. Patent Application No. 60/534,157, which is entitled“Electrochemical Fabrication Methods Incorporating DielectricMaterials”. The fourth of these filings is U.S. Patent Application No.60/533,891, which is entitled “Methods for Electrochemically FabricatingStructures Incorporating Dielectric Sheets and/or Seed layers That ArePartially Removed Via Planarization”. A fifth such filing is U.S. PatentApplication No. 60/533,895, which is entitled “ElectrochemicalFabrication Method for Producing Multi-layer Three-DimensionalStructures on a Porous Dielectric”. Additional patent filings thatprovide teachings concerning incorporation of dielectrics into the EFABprocess include U.S. patent application Ser. No. 11/139,262, filed May26, 2005 by Lockard, et al., and which is entitled “Methods forElectrochemically Fabricating Structures Using Adhered Masks,Incorporating Dielectric Sheets, and/or Seed Layers that are PartiallyRemoved Via Planarization”; and U.S. patent application Ser. No.11/029,216, now abandoned, filed Jan. 3, 2005 by Cohen, et al., andwhich is entitled “Electrochemical Fabrication Methods IncorporatingDielectric Materials and/or Using Dielectric Substrates”. These patentfilings are each hereby incorporated herein by reference as if set forthin full herein.

Some embodiments may employ diffusion bonding or the like to enhanceadhesion between successive layers of material. Various teachingsconcerning the use of diffusion bonding in electrochemical fabricationprocesses are set forth in U.S. patent application Ser. No. 10/841,384,now abandoned, which was filed May 7, 2004 by Cohen et al. which isentitled “Method of Electrochemically Fabricating Multilayer StructuresHaving Improved Interlayer Adhesion” and which is hereby incorporatedherein by reference as if set forth in full. This application is herebyincorporated herein by reference as if set forth in full.

Some embodiments may incorporate elements taught in conjunction withother medical devices as set forth in various U.S. patent applicationsfiled by the owner of the present application and/or may benefit fromcombined use with these other medical devices: Some of these alternativedevices have been described in the following previously filed patentapplications: (1) U.S. patent application Ser. No. 11/478,934, by Cohenet al., and entitled “Electrochemical Fabrication ProcessesIncorporating Non-Platable Materials and/or Metals that are Difficult toPlate On”; (2) U.S. patent application Ser. No. 11/582,049, by Cohen,and entitled “Discrete or Continuous Tissue Capture Device and Methodfor Making”; (3) U.S. patent application Ser. No. 11/625,807, by Cohen,and entitled “Microdevices for Tissue Approximation and Retention,Methods for Using, and Methods for Making”; (4) U.S. patent applicationSer. No. 11/696,722, by Cohen, and entitled “Biopsy Devices, Methods forUsing, and Methods for Making”; (5) U.S. patent application Ser. No.11/734,273, by Cohen, and entitled “Thrombectomy Devices and Methods forMaking”; (6) U.S. Patent Application No. 60/942,200, by Cohen, andentitled “Micro-Umbrella Devices for Use in Medical Applications andMethods for Making Such Devices”; and (7) U.S. patent application Ser.No. 11/444,999, by Cohen, and entitled “Microtools and Methods forFabricating Such Tools”. Each of these applications is incorporatedherein by reference as if set forth in full herein.

Though the embodiments explicitly set forth herein have consideredmulti-material layers to be formed one after another. In someembodiments, it is possible to form structures on a layer-by-layer basisbut to deviate from a strict planar layer on planar layer build upprocess in favor of a process that interlaces material between thelayers. Such alternative build processes are disclosed in U.S.application Ser. No. 10/434,519, filed on May 7, 2003, now U.S. Pat. No.7,252,861, entitled Methods of and Apparatus for ElectrochemicallyFabricating Structures Via Interlaced Layers or Via Selective Etchingand Filling of Voids. The techniques disclosed in this referencedapplication may be combined with the techniques and alternatives setforth explicitly herein to derive additional alternative embodiments. Inparticular, the structural features are still defined on aplanar-layer-by-planar-layer basis but material associated with somelayers are formed along with material for other layers such thatinterlacing of deposited material occurs. Such interlacing may lead toreduced structural distortion during formation or improved interlayeradhesion. This patent application is herein incorporated by reference asif set forth in full.

The patent applications and patents set forth below are herebyincorporated by reference herein as if set forth in full. The teachingsin these incorporated applications can be combined with the teachings ofthe instant application in many ways: For example, enhanced methods ofproducing structures may be derived from some combinations of teachings,enhanced structures may be obtainable, enhanced apparatus may bederived, and the like.

U.S. Pat. App. Ser. No., Filing Date U.S. App. Pub. No., Pub. Date U.S.Pat. No., Issue Date Inventor, Title 09/493,496 - Jan. 28, 2000 Cohen,“Method For Electrochemical Fabrication” U.S. Pat. No. 6,790,377 - Sep.14, 2004 10/677,556 - Oct. 1, 2003 Cohen, “Monolithic StructuresIncluding Alignment 2004-0134772 - Jul. 15, 2004 and/or RetentionFixtures for Accepting Components” 10/830,262 - Apr. 21, 2004 Cohen,“Methods of Reducing Interlayer 2004-0251142A - Dec. 16, 2004Discontinuities in Electrochemically Fabricated Three- U.S. Pat. No.7,198,704 - Apr. 3, 2007 Dimensional Structures” 10/271,574 - Oct. 15,2002 Cohen, “Methods of and Apparatus for Making High 2003-0127336A -Jul. 10, 2003 Aspect Ratio Microelectromechanical Structures” U.S. Pat.No. 7,288,178 - Oct. 30, 2007 10/697,597 - Dec. 20, 2002 Lockard, “EFABMethods and Apparatus Including 2004-0146650A - Jul. 29, 2004 SprayMetal or Powder Coating Processes” 10/677,498 - Oct. 1, 2003 Cohen,“Multi-cell Masks and Methods and Apparatus 2004-0134788 - Jul. 15, 2004for Using Such Masks To Form Three-Dimensional U.S. Pat. No. 7,235,166 -Jun. 26, 2007 Structures” 10/724,513 - Nov. 26, 2003 Cohen,“Non-Conformable Masks and Methods and 2004-0147124 - Jul. 29, 2004Apparatus for Forming Three-Dimensional Structures” U.S. Pat. No.7,368,044 - May 6, 2008 10/607,931 - Jun. 27, 2003 Brown, “Miniature RFand Microwave Components 2004-0140862 - Jul. 22, 2004 and Methods forFabricating Such Components” U.S. Pat. No. 7,239,219 - Jul. 3, 200710/841,100 - May 7, 2004 Cohen, “Electrochemical Fabrication Methods2005-0032362 - Feb. 10, 2005 Including Use of Surface Treatments toReduce U.S. Pat. No. 7,109,118 - Sep. 19, 2006 Overplating and/orPlanarization During Formation of Multi-layer Three-DimensionalStructures” 10/387,958 - Mar. 13, 2003 Cohen, “ElectrochemicalFabrication Method and 2003-022168A - Dec. 4, 2003 Application forProducing Three-Dimensional Structures Having Improved Surface Finish”10/434,494 - May 7, 2003 Zhang, “Methods and Apparatus for Monitoring2004-0000489A - Jan. 1, 2004 Deposition Quality During ConformableContact Mask Plating Operations” 10/434,289 - May 7, 2003 Zhang,“Conformable Contact Masking Methods and 2004-0065555A - Apr. 8, 2004Apparatus Utilizing In Situ Cathodic Activation of a Substrate”10/434,294 - May 7, 2003 Zhang, “Electrochemical Fabrication MethodsWith 2004-0065550A - Apr. 8, 2004 Enhanced Post Deposition Processing”10/434,295 - May 7, 2003 Cohen, “Method of and Apparatus for FormingThree- 2004-0004001A - Jan. 8, 2004 Dimensional Structures Integral WithSemiconductor Based Circuitry” 10/434,315 - May 7, 2003 Bang, “Methodsof and Apparatus for Molding 2003-0234179 A - Dec. 25, 2003 StructuresUsing Sacrificial Metal Patterns” U.S. Pat. No. 7,229,542 - Jun. 12,2007 10/434,103 - May 7, 2004 Cohen, “Electrochemically FabricatedHermetically 2004-0020782A - Feb. 5, 2004 Sealed Microstructures andMethods of and Apparatus U.S. Pat. No. 7,160,429 - Jan. 9, 2007 forProducing Such Structures” 10/841,006 - May 7, 2004 Thompson,“Electrochemically Fabricated Structures 2005-0067292 - May 31, 2005Having Dielectric or Active Bases and Methods of and Apparatus forProducing Such Structures” 10/434,519 - May 7, 2003 Smalley, “Methods ofand Apparatus for 2004-0007470A - Jan. 15, 2004 ElectrochemicallyFabricating Structures Via Interlaced U.S. Pat. No. 7,252,861 - Aug. 7,2007 Layers or Via Selective Etching and Filling of Voids” 10/724,515 -Nov. 26, 2003 Cohen, “Method for Electrochemically Forming2004-0182716 - Sep. 23, 2004 Structures Including Non-Parallel Mating ofContact U.S. Pat. No. 7,291,254 - Nov. 6, 2007 Masks and Substrates”10/841,347 - May 7, 2004 Cohen, “Multi-step Release Method for2005-0072681 - Apr. 7, 2005 Electrochemically Fabricated Structures”60/533,947 - Dec. 31, 2003 Kumar, “Probe Arrays and Method for Making”60/534,183 - Dec. 31, 2003 Cohen, “Method and Apparatus for MaintainingParallelism of Layers and/or Achieving Desired Thicknesses of LayersDuring the Electrochemical Fabrication of Structures” 11/733,195 - Apr.9, 2007 Kumar, “Methods of Forming Three-Dimensional 2008-0050524 - Feb.28, 2008 Structures Having Reduced Stress and/or Curvature” 11/506,586 -Aug. 8, 2006 Cohen, “Mesoscale and Microscale Device Fabrication2007-0039828 - Feb. 22, 2007 Methods Using Split Structures andAlignment Elements” 10/949,744 - Sep. 24, 2004 Lockard,“Three-Dimensional Structures Having 2005-0126916 - Jun. 16, 2005Feature Sizes Smaller Than a Minimum Feature Size U.S. Pat. No.7,498,714 - Mar. 3, 2009 and Methods for Fabricating”

Though various portions of this specification have been provided withheaders, it is not intended that the headers be used to limit theapplication of teachings found in one portion of the specification fromapplying to other portions of the specification. For example, it shouldbe understood that alternatives acknowledged in association with oneembodiment, are intended to apply to all embodiments to the extent thatthe features of the different embodiments make such applicationfunctional and do not otherwise contradict or remove all benefits of theadopted embodiment. Various other embodiments of the present inventionexist. Some of these embodiments may be based on a combination of theteachings herein with various teachings incorporated herein byreference.

In view of the teachings herein, many further embodiments, alternativesin design and uses of the embodiments of the instant invention will beapparent to those of skill in the art. As such, it is not intended thatthe invention be limited to the particular illustrative embodiments,alternatives, and uses described above but instead that it be solelylimited by the claims presented hereafter.

What is claimed is:
 1. A method of selectively removing target tissuefrom a body, the method comprising: providing a tissue cuttinginstrument capable of automatically distinguishing between target tissueto be removed and non-target tissue, the tissue cutting instrumentcomprising: at least two oppositely rotating cutting elements covered bya cutter housing, the at least two cutting elements each having at leastone cutting surface configured to shear tissue against a cutting surfaceof an opposing cutting element, wherein the at least two oppositelyrotating cutting elements have two separate, parallel and laterallyoffset axes of rotation, wherein each of the at least two oppositelyrotating cutting elements is configured to rotate at least one full turnabout one of the axes of rotation, wherein the cutting surfaces eachcomprise at least two cutting teeth and at least one trough between theteeth, the at least one trough having a nominal diameter of about 2 toabout 100 microns, wherein a tip to tip distance between the teeth is atleast two times the trough diameter, the cutter housing having a tissueaccess opening adjacent to a portion of the cutting elements throughwhich tissue must extend to contact the cutting elements, wherein amaximum outside diameter of each of the at least two cutting elements isrecessed from the tissue access opening in the cutter housing by afixed, predetermined distance, wherein the instrument is configured toremove a maximum of about 2 to about 100 microns of target tissue at atime; urging the instrument against the target tissue and the non-targettissue; and allowing the instrument to cut the target tissue whileautomatically avoiding cutting of the non-target tissue.
 2. The methodof claim 1, further comprising automatically discontinuing tissuecutting once the instrument is contacting only the non-target tissue. 3.The method of claim 1, further comprising allowing the instrument toremove the target tissue from the body as it is being cut.
 4. The methodof claim 1, wherein the tissue cutting instrument is configured todistinguish between the target tissue and the non-target tissue bysensing an electrical current level being delivered to a cutter motor.5. The method of claim 1, wherein the tissue cutting instrument isconfigured to distinguish between the target tissue and the non-targettissue by electronically sensing a cutter drive velocity.
 6. The methodof claim 1, wherein the tissue cutting instrument is configured to senseat least one parameter selected from the group consisting of:capacitance, inductance, optical changes, pressure, proximity andposition.
 7. The method of claim 1, wherein the tissue cuttinginstrument is configured to allow cutting of the target tissue whileautomatically avoiding cutting of non-target tissue by permittingmodulation of a cutter speed.
 8. The method of claim 1, wherein thetissue cutting instrument is configured to allow cutting of the targettissue while automatically avoiding cutting of non-target tissue bypermitting modulation of suction in a port adjacent to a cutter head ofthe instrument.
 9. The method of claim 1, wherein the at least twocutting elements are tuned to capture elements of the target tissue andreject elements of the non-target tissue.
 10. The method of claim 9,wherein the nominal diameter of the at least one through of each of thecutting surfaces is matched to a diameter of a fiber or fiber bundle ofthe target tissue.
 11. The method of claim 9, wherein the tip to tipdistance between the cutting teeth is matched to a diameter of a fiberbundle of the target tissue.
 12. The method of claim 1, wherein themaximum outside diameter is recessed by an amount that is at least about5 microns and less than about 100 microns.
 13. The method of claim 1,wherein the target tissue comprises endocardium and the non-targettissue comprises myocardium.
 14. The method of claim 1, wherein thetarget tissue comprises mucosa and the non-target tissue comprisessubmucosa.
 15. The method of claim 1, wherein the target tissuecomprises flavum and the non-target tissue comprises dura mater.
 16. Themethod of claim 1, wherein the target tissue comprises flavum and thenon-target tissue comprises nerve roots.
 17. The method of claim 1,wherein the target tissue comprises flavum and the non-target tissuecomprises bone.
 18. The method of claim 1, wherein the target tissuecomprises prostate tissue and the non-target tissue comprises nervetissue.
 19. The method of claim 1, wherein the target tissue comprisessoft tissue and the non-target tissue comprises tendon.
 20. The methodof claim 1, wherein the target tissue comprises soft tissue and thenon-target tissue comprises cartilage.
 21. The method of claim 1,wherein the target tissue comprises cartilage and the non-target tissuecomprises bone.
 22. The method of claim 1, wherein the target tissuecomprises cancerous cells.
 23. The method of claim 1, wherein the targettissue comprises labrum.
 24. The method of claim 1, wherein the targettissue comprises plaque and the non-target tissue comprises a vascularwall.
 25. The method of claim 1, wherein the target tissue comprisescalcified tissue and the non-target tissue comprises a vascular wall.26. The method of claim 1, wherein the target tissue comprises athrombus and the non-target tissue comprises a vascular wall.
 27. Themethod of claim 1, wherein the target tissue comprises an embolus andthe non-target tissue comprises a vascular wall.